How to set up the parts of Hylki that need more than a switch. The README covers installing, FEATURES.md lists what the app does, and KEYBOARD_SHORTCUTS.md the keyboard.
Contents
- Configuration
- GNOME Online Accounts
- On This Computer
- OAuth (Google / Microsoft)
- Cloud attachments (Nextcloud, OneDrive, Dropbox, Seafile)
- Address books
- CardDAV accounts
- LDAP directories
- Translating messages
- Grammar checking
- Writing in Markdown or HTML
- OpenPGP (encrypted and signed mail)
- Send with Hylki from GNOME Files
- Privacy
Add accounts from Settings → Accounts in the app. For a plain IMAP/SMTP
account you only need the server and an app-specific password. See
accounts.toml.example for the on-disk format:
passwords you enter there are migrated into the system keyring on first run and
removed from the file.
Shared hosting often serves mail for many domains under one certificate in
the host's own name, so mail.example.org answers with a certificate for
server12.hostingcompany.net and the connection test reports that the names
differ. Settings → Accounts → the account → Accept a certificate for
another name waives that one check for the account's IMAP, POP3 and SMTP
connections; the certificate must still be valid and signed by a trusted
authority. Leave it off unless the test names this problem, and prefer
entering the host the certificate is actually for when you know it. Stored
on the account as tls_accept_hostname_mismatch in accounts.toml. The
connection test's text can be selected and copied.
Any mail account set up in GNOME Settings → Online Accounts can be imported: Google, Microsoft 365 and plain IMAP and SMTP accounts alike. They are listed on the first-run wizard's first account page, which can be skipped, and under Settings → Accounts → GNOME Online Accounts, where a switch brings one into Hylki. An account added in GNOME Settings while Hylki is open joins the list as soon as GNOME announces it; the refresh button beside Add Account… looks again at once.
GNOME keeps such an account's address, servers and password, and Hylki
follows it. The password is read from GNOME Online Accounts each time the
account connects, and server changes made in GNOME Settings are picked up
while Hylki runs, so nothing is typed twice. For an IMAP and SMTP account
Hylki also uses what GNOME records about each server: TLS from the start or
a STARTTLS upgrade, whatever the port, and a certificate accepted in GNOME
Settings although it does not verify, as a home server's self-signed one
does not. Stored on the account as the security table in accounts.toml.
A JMAP account (RFC 8620 and 8621) reads and sends mail over HTTPS, so it needs one server address and no SMTP settings. The Provider list has three JMAP entries:
- Fastmail (JMAP) fills in Fastmail's session URL and signs in with an API token rather than the account password. Make the token in Fastmail's settings, under Privacy & Security, with access to mail and to sending it, and enter it in the API Token row.
- Stalwart (JMAP) and JMAP Server take the server as a host name
(
mail.example.org, reached over HTTPS on 443, or the port in the Port row) or a full URL, and sign in with the username and password. Turn on Sign in with an API token for a server that takes a token instead. They differ only in the account's mark: Stalwart's logo, or a red JMAP tile.
For a host name, Hylki reads the session resource at /.well-known/jmap.
A URL with a path is tried as the session resource itself
(https://api.fastmail.com/jmap/session), then as a prefix with
/.well-known/jmap under it. The API, download, upload and push addresses
come from the session.
A server names itself in that session, with the host it was set up with.
When the address is entered as a URL with its scheme (http://10.0.0.5:8080,
say, for a server on a private network or behind a tunnel), Hylki uses that
origin in place of the one the server advertises for itself; a URL on a
different host, such as the separate one Fastmail serves attachments from,
is left as advertised.
Folders come with their roles from the server, so Sent, Drafts, Junk and
Trash need no detection. Read state, stars and tags are the server's own
keywords, a message keeps its id when it moves, and threading uses the
Message-ID, In-Reply-To and References headers the listing carries. Sending
goes through the server's EmailSubmission, which files the copy in Sent
(or the folder chosen under Sent copies) before the send is reported done.
New mail arrives over the server's EventSource push channel when push is
on for the account, with a poll as the fallback. Marking a message as spam
or not spam sets the $junk and $notjunk keywords the server's filter
learns from. The server's sending identities are offered in the composer's
From row (see The From address), and an alias has no
SMTP settings of its own.
Tested against Stalwart, with a password and with a bearer token; Fastmail
speaks the same standard but has not been tried by hand. In accounts.toml
the account has protocol = "jmap", the server in imap_host, and
jmap_token = true when it signs in with a token, which the keyring keeps
where a password would be. An account made from the JMAP Server entry has
jmap_generic = true.
An account's main folders (Inbox, Drafts, Sent, Archive, Junk, Trash) come
first, in that order, then its custom folders, each under its parent.
Folders kept inside the Inbox on the server (INBOX.Ablage, INBOX/Lists)
are listed under the Inbox row, with an arrow on it to fold them away, when
the account has folders outside the Inbox too, as Roundcube and Apple Mail
show them. A server that keeps every folder inside the Inbox (an INBOX.
prefix, as on Courier and some Dovecot setups) has them under Folders
instead, without the prefix. How
the custom folders are sorted is chosen in Settings → Sidebar → Folder
order, for every account:
- Custom Order (the default): by the name shown, with any folder you dragged kept where you put it. A folder that was never dragged, such as one created later, goes just after the sibling that comes before it by name.
- Name (A to Z) and Name (Z to A): by the name shown, whatever was
dragged. Gmail's
[Gmail]/Importantsorts as "Important", as it does in Thunderbird. - Full Path: by the whole path on the server, the way Gmail on the web lists labels.
An account can have its own: Folder Order → Sort by in the account's settings (Settings → Mail Accounts → the account), or the right-click menu of the account's Folders heading in the sidebar. Follow Settings goes back to the choice in Settings → Sidebar.
To put folders in an order of your own, drag them up or down the list. While a folder is dragged, a line in the accent color shows the gap between folders where it will land, indented to the level it lands at. Dragging a custom folder puts its account in Custom Order, every other folder staying where the previous sort showed it.
- In a gap among its own siblings, the folder only changes places.
- In a gap at another level, the folder is moved to that level on the server, the same move as dropping it on a folder, and then takes that place. Its sub-folders go with it.
- Over the middle third of a folder, that folder is outlined, and the dragged folder is moved inside it on the server.
The main folders only change places among themselves, and keep their order
whichever sort is chosen. Gmail lists some folders inside [Gmail], which
is not a folder of its own; they are drawn at the top level, and only
folders already inside [Gmail] can be dropped among them. Renaming a
folder keeps its place.
The order is kept on this computer, in sidebar.toml, and an account's
own sort in accounts.toml as folder_sort; only a move to another level
changes anything on the server. IMAP has no folder order, so other mail
apps and Gmail on the web each keep their own. Reset Folder Order, in
the right-click menu of the account's header or its Folders heading, forgets
what was dragged. The item is there only once something has been.
The chevrons open and close the items in the sidebar. Clicking a folder opens it and leaves its sub-folders as they were, and double-clicking it opens or closes them as its chevron does. The Folders, Labels and Tags headings of an account work the same way: a chevron or a double click opens or closes the section, and a single click elsewhere on it does nothing. Clicking Inboxes, Starred, Sent, Drafts, Archive, Junk or Trash in the unified section, or Favorites, Filters, Tags or Contacts, opens the combined list without showing each account's folder under it, and double-clicking it opens or closes that list as its chevron does. An account's header works the same way: its chevron, or a double click on the header, opens or closes its folders, and a single click elsewhere on it does nothing. Settings → Sidebar → Fold accounts with one click brings back the single click anywhere on the header. In the icon rail, which has no chevrons, a click on a section's icon opens or closes it, and a long press or a double click opens or closes the unified rows. A click on an account's avatar opens that account's Inbox, and a long press or a double click opens or closes its folders; with Fold accounts with one click on, a click opens or closes them instead.
Settings → Sidebar → Unified chooses the unified section's rows. Inboxes, Starred, Sent, Drafts, Archive and Snoozed are on until switched off, and Snoozed is listed only while mail is snoozed; Junk and Trash are off until switched on. In the unified Junk and Trash, Not Spam and Move to Inbox send each message to its own account's Inbox, and the right-click menu of each account's row beneath has Empty Junk… or Empty Trash…. The same item on the unified Junk or Trash row itself empties that folder in every account in the unified section at once, after a confirmation that lists them.
Settings → Sidebar → Sections places Filters, Tags, Favorites and Contacts Above the accounts, Below the accounts or Off, which leaves it out of the sidebar. Contacts can also be In the footer, where it is by default: a row above Attachments, without its address books under it. The same Contacts placement is in Settings → Contacts. Wherever they are, they are rows like the unified section's, with a chevron that opens their list. Section style set to Tree style draws all four as a tree instead: the caret that opens and closes the list stands where the icon was, and the row has no chevron at its end. Clicking the name opens the combined view either way.
Right-click any folder in the sidebar and choose Add to Favorites to list it in a Favorites row above the accounts (Settings → Sidebar → Sections can move it). Favorites can come from any account, keep the order they were added in, and show their unread counts; the folder's glyph takes its account's color. Clicking Favorites lists the mail of every favorite folder together; its chevron, or a double click, opens or closes the list. Remove from Favorites, in the same menu or on the favorite itself, takes it out, and the row goes when the last one does. Favorites show with a single account too, and for an account left out of All Inboxes.
They are kept on this computer, in sidebar.toml as favorites. A folder
renamed or moved in Hylki stays a favorite under its new name; one deleted
leaves the list.
A smart folder is a saved search. It lists the messages that match its conditions and sits in a Smart Folders row at the end of the unified section, each with its unread count. Settings → Smart Folders → Add Smart Folder… makes one; so do New Smart Folder… in the row's right-click menu and in the command palette. Right-clicking a smart folder edits or deletes it. Deleting one takes only the search away, never the mail.
- Account: one account, or all accounts, meaning those in the unified section.
- Folders: one kind of folder (Inbox, Sent, Drafts, Archive, Junk or Trash), or every folder but Trash and Junk.
- Conditions: starred or not, unread or read, has attachments, tagged with a tag or any tag, and the text conditions filters use: From address and name, To or Cc, Reply-To, the message preview, and whether the sender is in Contacts. Condition matching says whether all must match or any one may.
"Sent mail that is starred or tagged" is Folders: Sent, with Starred and
Tagged (any tag) as conditions and Any one may match. A smart folder
searches the mail on this computer, so it finds what has been synced, and
lists at most 5,000 messages per account. They are kept in
smart_folders.toml.
On a Gmail account, the labels Gmail has on a message show as pills beside its tags, in the message list and the reader. Gmail's own labels, such as Inbox, Important and Starred, are left out, as is the label of the folder being read. Each label has a color of its own, picked from its name; a tag named like the label sets the color instead. A label with the same name or keyword as a tag is that tag: it shows as the tag, the tag's view in the sidebar lists the message, and smart folders and the tag menus count it.
Tagging a message on a Gmail account puts a label named like the tag on it, so Gmail's own apps show the tag too, and keeps the IMAP keyword other mail programs read; taking the tag off removes both. A label Hylki has just made appears as a folder after the next folder check, as every Gmail label does. Labels are read with each sync of a folder's newest mail; mail synced before Hylki read labels gets them once, in the background.
Right-click a folder in the sidebar and choose Hide Folder to take it out of the sidebar and out of syncing: the folder is not listed, its unread count is not fetched, and its mail is not indexed until it is shown again. Only plain folders can be hidden; the folders holding a role (Sent, Drafts, Trash, Junk, Archive) stay, since mail is filed into them. Hiding a folder hides its sub-folders with it.
The hidden folders are listed under Settings → Accounts → the account →
Hidden Folders, each with a Show button that brings it back on Save.
They are stored on the account as hidden_folders in accounts.toml.
An Exchange server lists its calendar, contacts, tasks, notes and journal folders over IMAP as if they were mail folders, along with Outbox, Sync Issues, Conversation History and Scheduled. Hylki hides these the first time it lists such an account, and only when the listing looks like Exchange (at least two of Calendar, Contacts, Tasks and Journal at the top level), so a "Notes" folder on any other server is left alone. The look is taken once per account; a folder brought back from the Hidden Folders list stays back.
Settings → Accounts → the account → Show in All Inboxes decides whether the account's mail is merged into the unified section at the top of the sidebar. Switched off, the account's folders are left out of the unified Inboxes, Starred, Sent, Drafts, Archive, Junk, Trash and Snoozed rows, their account lists and unread counts, and the account's filter folders and tagged mail are left out of the unified Filters and Tags. The account keeps its own section in the sidebar, and a search still covers its mail.
The tray icon's count and new-mail notifications still include the
account. Clicking a notification for it opens the account's own Inbox.
With fewer than two accounts left in the unified section, it is not shown,
as with a single account, and Open at startup: All Inboxes opens the
first account's Inbox instead.
Stored on the account as in_unified = false in accounts.toml; without
the key an account is included.
Move To lists the folders of the account the mail is in first, then those of every other account that can take mail, each under its account's name. Dragging messages onto another account's folder in the sidebar does the same.
The message is copied into the other account with its read and starred state. Only once that copy is stored is the original moved to its own account's Trash (or erased, where the account has no Trash), so a move that fails leaves the message where it was and says why.
Undo (Ctrl+Z) takes the original back out of its account's Trash and puts the copy in the other account's Trash; Redo does the move again. A move from or to an account without a Trash folder cannot be undone.
IMAP and JMAP accounts can receive mail this way, and so can On This Computer. A Microsoft account and a POP3 account can be moved from but not into: Microsoft files a message added to a folder as a draft, and POP3 has only an inbox.
Copy To…, in a message's right-click menu in the list and in the reader, opens the same picker as Move To. The message is stored again in the folder picked, with its read and starred state, and the original stays where it is. It works within an account and across accounts, into any folder of an account that can receive mail (see above), and a copy is not undone with Ctrl+Z.
Settings → Accounts → On This Computer → Add adds folders kept on this computer rather than on a server, as Evolution's account of the same name does. It starts with a Trash, and an Inbox that is shown only while it holds mail, as mail copied from an account goes to a folder named after the account. Folders are made, renamed and deleted as on any account, and mail comes in by being moved or copied there from another account with Move To or Copy To, or by dragging it onto one of its folders (see Moving mail to another account). Moving mail to a folder it does not have yet, such as Archive or Snoozed, makes the folder.
Nothing is sent from it: it has no From address in the composer, and a reply to a message filed there is sent from the account the message was addressed to, or from the first account in the sidebar. Read receipts, invitation answers and unsubscribe mail for its messages go out the same way.
Every message is rendered into the cache in the background, so a search covers the whole archive, and clearing downloaded mail in Settings → System leaves it alone. It is not in All Inboxes until Show in All Inboxes is switched on. Empty Junk automatically and Empty Trash automatically count the days from when a message was moved into the folder.
Settings → Accounts → the account → Syncing → Copy mail to On This
Computer copies every message of the account into a folder named after it,
with the account's folders inside: Inbox, Sent and the rest. The account
downloads its mail in the background to do it, as Keep mail cached
does, and leaves out Trash, Junk and Drafts. New mail is copied within about
a minute of the account receiving it. While messages are being copied the
refresh button turns, and the status bar, when opened, says how many are
left. What is deleted or moved on the
server afterwards stays in the copy as it was, and a message moved to
another folder on the server is not copied again. Switching the setting on
adds On This Computer when there is none. Which messages are copied is
listed in hylki-copied/ beside the folders.
Settings → Accounts → On This Computer → Import takes mail from another program's folders:
- Maildir folders: a Maildir tree, such as Evolution's own On This
Computer folders in
~/.local/share/evolution/mail/local/(where the picker opens when they are there) or Dovecot's. The tree's Inbox goes to the Inbox and every other folder to the folder of the same name, with its read, starred and replied state and Dovecot's tags. - Mbox files: one or more mbox files, such as Thunderbird's, each into a
folder named after the file. Thunderbird's
Name.sbddirectories become the folders above it, and its read, starred, replied and forwarded marks are kept. A message the file marks as deleted is left out.
A message whose Message-ID its folder already holds is left out, so an import run twice adds nothing. The status bar counts the import as it goes, and the folders appear when it is done.
The folders are a Maildir++ tree in ~/.local/share/hylki/local-mail/
(~/.var/app/co.hyprlab.Hylki/data/hylki/local-mail/ in the Flatpak): the
Inbox at the top, every other folder a .Name directory beside it, a
sub-folder .Parent.Child. Each message is one file, read, starred and
replied to are letters in its name, and tags are listed in
dovecot-keywords, as Dovecot keeps them. Messages dropped into a folder's
new directory are found when the folder opens. Removing the account leaves
the folders where they are, and adding it again finds them.
Delete from Server… in the right-click menu of a file in the attachment drawer, or in the attachment gallery, takes that one file out of the message on the server, to save space there. The rest of the message stays: its text, its other files, where it is filed, its read, starred and tag state, and its date. Hylki asks first, as the change reaches every device that reads the account and cannot be undone. Save the file first if you want to keep a copy. While the server works, the file shows pale red with "Deleting…" in place of its buttons, then fades out; if the server refuses, it comes back as it was.
An IMAP or JMAP server cannot edit a message, so Hylki stores a copy without the file and then deletes the original; the copy stands where the original was. In place of the file the copy carries a short note in the format Thunderbird uses, so Thunderbird shows it as a deleted attachment and Hylki leaves it out of the list. A Microsoft account deletes the file from the message itself.
It is refused where it would not save space or would break the message:
- Gmail, which keeps every message in All Mail as well, so the original would stay there, file and all.
- POP3, which has no way to change a message on the server.
- A signed or encrypted message, where removing a file breaks the signature or cannot be done at all.
- A message that is nothing but the file, which is better deleted whole.
Microsoft signs in with Hylki's own app, with or without GNOME Online Accounts: pick Microsoft 365 / Outlook in the first-run wizard or in Settings → Mail Accounts, and sign in in the browser. The account's name and address are filled in from the sign-in, and its mail is read and sent through Microsoft Graph. This also works where GNOME Online Accounts cannot add the account, as with personal accounts on GNOME 46 (Ubuntu 24.04, Linux Mint 22).
Personal accounts (outlook.com, hotmail.com, live.com) approve Hylki
themselves the first time. A work or school account may need its
organization's administrator to approve Hylki once for everyone, at
https://login.microsoftonline.com/organizations/adminconsent?client_id=01cdc012-c8d8-4d03-822c-76696a01c14e;
Hylki shows that link when Microsoft refuses a sign-in for want of approval.
An organization that has approved another mail app's registration, and not
Hylki's, can sign in with that one instead. The Advanced row on the
account's page takes its Client ID, a Tenant (common,
organizations, consumers, or the organization's directory ID or
domain), the Scopes it was approved for and its Redirect URI. Empty
rows keep Hylki's own. Scopes are Graph's short names, space-separated,
such as Mail.ReadWrite Mail.Send User.Read; offline_access is added if
it is missing. Hylki reads and sends mail, so only the mail scopes are used,
whatever else the list grants. A redirect URI that is not a localhost
address, such as Evolution's
https://login.microsoftonline.com/common/oauth2/nativeclient, makes the
sign-in run in a window of Hylki's instead of the browser, so the answer
can be caught; that window keeps nothing once it closes. Evolution's
registration is 20460e5d-ce91-49af-a3a5-70b6be7486d1 with that redirect.
An organization whose Conditional Access lets only a managed device sign in
refuses that window and any browser but its own. On a computer enrolled with
Microsoft's identity broker (microsoft-identity-broker from Intune, or
Himmelblau), Hylki asks the broker for a device sign-in cookie, as Evolution
does, and sends it with the sign-in page and with every token refresh. The
broker's account is the one with the address on the account's page, so enter
the address before signing in. Without a broker nothing changes. The
Flatpak is allowed to talk to the broker on the session bus
(com.microsoft.identity.broker1) for this alone.
Google signs in through GNOME Online Accounts. Add your Google account in GNOME Settings → Online Accounts, then import it in Hylki. Official builds don't bundle a Google OAuth client (Google's secret can't live in a public repo), so GNOME Online Accounts is the standard path. You can also use your own OAuth client (see below).
To use your own OAuth client (a fork, a self-hosted build, or to replace the
bundled ones), put it in ~/.config/hylki/oauth.toml:
[google]
client_id = "your-client-id.apps.googleusercontent.com"
client_secret = "your-client-secret"
[microsoft]
client_id = "your-azure-application-client-id" # public client, no secret
[dropbox]
client_id = "your-dropbox-app-key" # public client, no secretor via the HYLKI_GOOGLE_CLIENT_ID / HYLKI_GOOGLE_CLIENT_SECRET,
HYLKI_MICROSOFT_CLIENT_ID / HYLKI_MICROSOFT_CLIENT_SECRET and
HYLKI_DROPBOX_CLIENT_ID environment variables.
Bundling a Google client at build time (for maintainers): set the env vars
during the build and they're compiled in via option_env!:
HYLKI_GOOGLE_CLIENT_ID=... HYLKI_GOOGLE_CLIENT_SECRET=... cargo build --releaseSettings → Cloud Storage holds the accounts the composer's upload button can put files on. A file goes to the account's upload folder and a share link, with the size and any expiry, is placed in the message above your signature. Every kind of account can expire links after a number of days and protect them with a download password, shown to you to pass on separately. The account's settings are the defaults: the upload dialog in the composer shows them for each upload, where the expiry can be changed or removed, the password turned on or off, and a password of your own typed in place of the generated one.
-
OneDrive: through GNOME Online Accounts: add your Microsoft 365 account under Settings → Online Accounts, then pick it in the cloud account's editor. GOA holds the sign-in and refreshes the token, so Hylki stores no password or key. Uploads go into the upload folder (made when missing) and are shared with "anyone with the link". Link expiry and download passwords need a Microsoft 365 subscription or OneDrive for Business: a free personal OneDrive refuses the link when either is set, so a new OneDrive account starts with both off, and the editor says so. The connection check finds out what the drive's plan allows and greys out the rows it rules out, with the reason, in the account's settings and in the upload dialog. Uploads and plain links work on any OneDrive. Google Drive is not offered: GNOME Online Accounts does not ask Google for Drive access on every system, and Hylki carries no Google client of its own.
-
Nextcloud, ownCloud, OpenCloud: the server URL, your user name and an app password (made under Security in the server's personal settings). Uploads go over WebDAV; links come from the files-sharing API.
-
Behind Cloudflare (Nextcloud-kind and Seafile accounts): a self-hosted server reached through a Cloudflare domain or tunnel cannot take a request over 100 MB, Cloudflare's proxy limit. Switch on Server is behind Cloudflare in the account's editor and files bigger than 90 MB go up in 90 MB pieces the server stitches back together (Nextcloud's chunked-upload endpoint, Seafile's resumable upload); smaller files go as one request as before.
-
Seafile: the server URL, your e-mail and your password. If the account uses two-step verification, also enter the current code from your authenticator app: Hylki signs in with it once, gets an API token from the server and keeps that in the keyring instead of the password (Seafile's web interface shows no such token itself; one obtained another way, say from the
api2/auth-token/endpoint, can be pasted in the password field). Uploads go into a library (made when missing, "Hylki" by default) and a folder inside it. -
Dropbox: sign in through your browser. Dropbox only lets a registered app sign in, so make one for yourself; it takes a minute and stays private:
- Open dropbox.com/developers/apps signed in to your Dropbox and press Create app.
- Choose Scoped access, then the access type: App folder gives Hylki its own folder under Apps and nothing else, Full Dropbox puts uploads in the folder named in the account's settings.
- Give the app a name no one else has used ("Hylki for Jane", say) and press Create app.
- On the Permissions tab tick
account_info.read,files.content.writeandsharing.write, then press Submit. - On the Settings tab, under OAuth 2 → Redirect URIs, enter
http://localhost:41597/and press Add. The port is fixed because Dropbox matches redirect URIs exactly. - Copy the App key from the top of the Settings tab.
In Hylki, add a Dropbox account under Settings → Cloud Storage, paste the app key and press Connect with Dropbox; the browser opens, you approve the app, and the account's e-mail appears in the dialog. The app can stay in Development status, which allows your own account (Dropbox asks for a production review only past a few hundred users). A build can carry an app key of its own (the
[dropbox]entry inoauth.toml, orHYLKI_DROPBOX_CLIENT_IDat build time), in which case the field can stay empty. Link passwords and expiry dates are a paid Dropbox feature; on a Basic plan leave both off, or the share step reports it.
Settings → Contacts lists every address book Hylki reads contacts from, one row each, as Mail Accounts lists mail accounts: the Hylki book, the books on this computer that GNOME Contacts and Evolution keep, each GNOME Online Accounts account that keeps contacts (Google, Microsoft 365, Nextcloud, iCloud), each CardDAV account and each LDAP directory. A row names the account, what it holds, and where it was set up: Hylki, GOA or Evolution.
A row's switch uses the address book in Hylki or leaves it out: of Contacts, the composer's suggestions, sender pictures, the filters on Contacts and syncing. The switch is Hylki's own; GNOME Contacts and Evolution go on using the book. An account whose Contacts are switched off in GNOME Online Accounts has its switch greyed out, and says so.
The arrow at the end of a row opens the address book's page. Its Name field gives the account a name of its own in Hylki: in this list, and under its address books in the sidebar's Contacts list, while GNOME Contacts and Evolution keep the account's. An account's page lists its address books, each with a name that can be changed the same way, as Rename… in the sidebar does, and a switch of its own, under the account's switch. A name left blank, applied, is the account's or the book's own again. The Hylki book's page holds its import and export. A GNOME Online Accounts account's page has Open Online Accounts, where its sign-in is changed; a CardDAV account's and a directory's page is their form, with Remove.
Add Address Book… offers a CardDAV server, iCloud, Nextcloud, Fastmail, Yahoo and an LDAP directory, set up in Hylki, and Google and Microsoft 365, which are added in GNOME Online Accounts and then listed here; the refresh button beside it looks again for one just added there. Every kind but the Hylki book is kept by Evolution Data Server; without it, the page says so. Save new contacts in, at the foot of the page, sets the book a contact made in Hylki goes to.
Show names from Contacts, on the same page, names a sender or recipient whose address is in an address book by the name saved there, not the one the message gives: in the message list, the reader and the new-mail notification. A contact then reads the same on all their mail, and mail that puts a contact's name on another address shows the name it gave, which gives it away. Address books that fill themselves from mail (Collected Addresses, Recently Contacted, Other Contacts) are not used for this, and a contact saved without a name keeps the message's.
A contact's photo is the sender's circle in the message list and in the reader's message headers. Without one, the circle shows the sender's Gravatar or their domain's logo when those are switched on in Settings → Privacy, and otherwise their initials.
Hylki keeps an address book of its own, the Hylki Address Book, beside the address books of GNOME Contacts, which Evolution Data Server (EDS) holds. It is there whether EDS is installed or not. Its contacts are created, edited and deleted like any other, and their addresses and photos are used for suggestions and avatars.
The Contacts view searches as the message list does. The search button in the list's header, Ctrl+F or / shows the search field, and Esc, or leaving the field empty, hides it and clears the search. Settings → Contacts → Keep the search field open shows it at all times. Searching for "group" or "groups" lists every group, whatever its name. The button at the right of the header sorts the people by first name, last name or email. Its Show only column keeps the groups alone, or the people with a photo, an email address, a phone number, a street address, a birthday or a company, or those in no group. The button turns the accent color while a filter is on, and Clear Filters shows everything again.
Contacts is a row of the sidebar's footer, above Attachments, unless Settings → Sidebar → Sections places it elsewhere. In the footer, or with Contacts off, a dropdown over the list picks All Address Books or one of them, and a book lists its groups and then its contacts. Above or below the accounts, the row opens every contact, and its chevron opens the list beneath: the Hylki book first, then each account. An account with one address book is that book's row, with the account or server it is kept by in small type under its name; an account with several is a row of its own, with how many contacts they hold together, and its books under it. Every book shows how many contacts it holds, and its groups are under it. An account or a book with groups folds and opens with the caret beside it, as a folder with sub-folders does; the list, the accounts and the books stay open or folded as they were left. Picking a book lists its groups, by name, and then its contacts; picking an account lists the groups and contacts of all its books. Picking a book opens Contacts on its contacts alone; picking a group lists the group and then its people, with Remove from Group in their right-click menu. An LDAP directory, under Directories, is searched by typing. A book's right-click menu has New Contact and New Group, made in that book, and Rename…, which gives the book a name of its own in Hylki: in the sidebar, on its contacts' cards and wherever Hylki names it, while GNOME Contacts and Evolution keep the book's own. Use Its Own Name, in the same window, goes back to it. A group's menu has New Message, Edit Group and Delete Group….
Contacts dragged from the list onto a book in the sidebar are copied there, and stay where they were. With Ctrl held as they are dropped they move instead, after a question that names both books. Dropped onto a group, they join it, copied first into the group's book when it needs them (see Contact groups). A drag takes every contact selected with the one dragged. A book Hylki cannot write to, and a group it cannot change, take no drop.
Several contacts are selected together with Ctrl or Shift and a click, or Ctrl+A for the whole list. The right-hand pane then lists them, with Add to Group, which puts them in a group (those it can take: see Contact groups), Move to…, which moves them to another address book, and Delete…; a right-click on one of them offers the same. A move adds each contact to the book picked and removes it from the one it was in, locally and on the server, with its photo; a group that names it by its card in the old book loses it. Contacts in a book Hylki cannot write to are not moved. With a group picked in the sidebar, the pane has Remove from Group for them too.
A new contact, made with the + button, has an Address book row at the top of its form that picks where it is saved; it starts on the book picked in the sidebar, or on the default book when every book is shown. A contact being edited can move to another book from the same row, which then names the one it is in: saving asks first, and moves it with its changes. A contact's right-click menu has Move to Address Book too, and several selected together move with Move to… (see below). A move takes the contact out of its book and puts it in the other, locally and on the server, after a question that names both; a group in the old book that held the contact no longer has it. A contact in a book Hylki cannot write to stays where it is.
The contact form holds the photo, which Change Photo… replaces with an image file (made at most 512 pixels a side and kept in the card) and Remove Photo takes away; the name, nickname, organization, title and birthday (a day and a month, the year if known); email addresses and phone numbers, each with a label (Home, Work, Mobile, Fax); postal addresses, in their parts; websites; and a note. No field is required: a card with only a phone number, or only a company, is a contact, and one with no name is listed by its email address, nickname, company or phone number, which the list also shows under the name when there is no email address. Every card in every book is listed, so someone kept in two books shows twice, each with its book named.
The Hylki book's page in Settings → Contacts shows how many contacts it
holds, and has Import vCard files, Export as a vCard file (one .vcf
file with every contact, which other apps can import) and Delete all
contacts, which asks first and leaves the other books alone. Save new
contacts in, on the same page as the list, sets the default book for
contacts made in Hylki, from the Contacts view or with Add Sender to
Contacts. Until it is set, a new contact goes to the first writable EDS
book, or to the Hylki book when there is none.
Importing reads .vcf files into the Hylki book, from Settings or from the
import button in the Contacts view's header. A file can hold many contacts,
in vCard 2.1, 3.0 or 4.0. A contact with the same ID as one already in the
book updates it, and one without an ID is matched by its content, so
importing a file twice adds nothing new. A contact list in the file becomes
a group (see Contact groups). Entries with neither a name
nor an address are skipped; truncated or oversized entries
(over 5 MB) are counted as damaged; a second card with the same ID in one
file is skipped, so the first is kept. Files over 50 MB are refused, and
photos are used only when they are inside the file: nothing is fetched from
the web. A person who is in both an EDS book and the Hylki book appears in
each, with the book named, and once in the composer's suggestions.
The book is the file local_contacts.db in Hylki's data folder, kept apart
from the mail cache, so clearing the cache leaves it alone.
A group is a name for several people, such as a team or a club, that the composer offers like a contact. Typing part of its name in To, Cc or Bcc lists it among the suggestions with the number of people in it, and picking it adds a pill for each of them. People already in that field are not added twice.
A group can be set to Send as Bcc. Picking it in any field then puts its people in Bcc, and opens the Bcc row, so they do not see each other's addresses. To still needs at least one address, your own for example.
A group is listed in the sidebar under its address book, and picking it lists its people (see The Hylki address book).
New Group, under the + button in the Contacts view, makes a group in the address book picked at the top of the form: the Hylki book, a book on this computer, or a CardDAV book such as iCloud's. Google and Microsoft 365 keep no groups, so their books are not offered. Add people by typing part of a name or address and picking from the matches under the field, or by typing or pasting addresses and pressing Return. The matches are the composer's suggestions: your contacts, and the addresses in the mail you have sent and received, marked with a clock. ↓ and ↑ move through them and Return adds the one highlighted. Anyone with an address can be in a group, not only people in your contacts. A contact's right-click menu has Add to Group, and a group's card has New Message, which writes to everyone in it. The group's pencil, at the top of its card, changes its name, its people and the Bcc switch, and its Address book moves it to another book: saving makes the group there, with its people, and then removes it from the book it was in. Moved into a CardDAV book, its people are copied there as contacts when the book does not have them yet; moved into the Hylki book or one on this computer, whose groups hold addresses, its people with no email address are left out. The form says so when another book is picked.
The lists made in Evolution, kept in the books of Evolution Data Server, are shown and offered too, and Evolution's Hide addresses when sending mail to this list is the same as Send as Bcc. They can be changed in Hylki as well.
A group in the Hylki book or on this computer is saved as an Evolution list,
so Export as a vCard file carries it to Evolution, and back. A group in
a CardDAV book is saved as Apple Contacts and iCloud save theirs, which
the Apple apps, Fastmail and DAVx⁵ read as groups too. Such a group holds
contacts of its own book. A contact of another book put in it with Add
to Group is copied to the group's book first, whole: phone numbers,
photo and all, and the original stays where it was. Someone the book
already has, by address (or, with no address, by name), is not copied
again. Someone added in the group's form by typing an address is added to
the book as a contact with their name and address. The groups made by Apple
Contacts and iCloud can be changed in Hylki the same way. Such a group can
hold people with no email address, known by a phone number for example:
they are listed in it as having none, and mail to the group goes to the
others. An Evolution list holds addresses, so a contact with none cannot
join one.
Send as Bcc is kept in the group, where other apps pass it over. A vCard 4
group (KIND:group) is shown and offered with the people it names in the
same book, but is changed in the app it came from. Groups are not counted as contacts in Settings →
Contacts, and the people in a group do not count as contacts for the
filters below.
A filter condition can be Sender is in Contacts or Sender is not in Contacts, under Settings → Filters. They take no text. The sender's address is looked up in the address books Evolution Data Server keeps and in the Hylki book. Books that fill themselves from mail you exchange are left out, so writing to someone once does not make them a contact: they are recognised by an English name such as "Collected Addresses", "Recently contacted" or "Other contacts", and a book named in another language may still count. While any book cannot be read, or all of them are empty, neither condition matches, so mail is not filed as coming from a stranger by mistake. The books are read again in the background at most once a minute and after a contact changes.
A version of Hylki from before these conditions reads them as a From address condition with no text, which matches nothing.
Add Address Book… in Settings → Contacts adds the address books on a CardDAV server, such as Nextcloud, iCloud, Fastmail, Radicale or a mail provider's, without GNOME Online Accounts or Evolution. Their contacts are listed in Contacts, in the book list above them, and suggested in the composer; a contact added or changed in Hylki is saved to the server.
Pick CardDAV Server, or the service by name: iCloud, Fastmail and Yahoo fill in their server, and Nextcloud asks for yours. The form asks for:
- Server: the server's address is enough for most services, such as
nextcloud.example.org, and Hylki finds the address books on it. A full CardDAV address works too. A name withouthttps://is taken as HTTPS; writehttp://for a server without TLS, such as one on your own network. For iCloud, usecontacts.icloud.com. - User name and Password. A service that signs in with two steps wants an app password made for Hylki: iCloud, Fastmail, and Nextcloud with two-factor sign-in among them.
Saving looks for the address books and says how many it found, or why it found none (a password the server refused, a server it could not reach). The account's row lists its address books by name, or what went wrong. Its page has the form, the address books with a switch each, and Remove, which removes the account and its address books from this computer, leaving the server as it is.
Google and Microsoft 365 address books are added in GNOME Online Accounts instead, which Add Address Book… points to: Google takes no password over CardDAV, and Microsoft 365 has no CardDAV.
An account is kept by Evolution Data Server, the service GNOME Contacts and
Evolution keep their address books in, as one of Evolution's own collection
accounts. Hylki adds no CardDAV client of its own, so an account set up in
Evolution's collection accounts is listed here as well, and one added here
shows in Evolution and GNOME Contacts. Evolution Data Server keeps the
password in the keyring, signs in with it by itself and syncs the address
books. While Hylki runs it keeps every address book that syncs with a server
open, so they stay up to date on desktops with no GNOME Contacts to do it,
and opening Contacts fetches what changed if that was more than five minutes
ago. Away from GNOME, Evolution Data Server has to be installed: it is the
evolution-data-server package on every major distribution and runs without
GNOME. Without it, the page says so.
The directories the composer looks recipients up in are added in Settings → Contacts, with Add Address Book… → LDAP Directory, and listed there with the other address books. Once three characters of a name or address are typed in To, Cc or Bcc, each directory that is switched on is asked for people whose name, surname or address starts with them, and the answers join the suggestions from GNOME Contacts and your mail. Nothing is copied from the directory to your machine.
The search in Contacts asks the directories the same way. The people they hold are listed after your contacts, under In Directories, with the directory's name beside each address. Selecting one shows the entry: an address starts a message, and Add to Contacts copies the person into the default address book. Each directory is also in the address book list above the contacts, by name after the address books: picking it shows only the people the search finds there. A directory switched on in Evolution is searched without restarting Hylki.
A directory is an address book in Evolution Data Server, the service GNOME Contacts and Evolution keep theirs in. Hylki adds no LDAP client of its own, so a directory set up in Evolution is listed here as well, and one added here shows in Evolution. Removing one removes it for both.
- Server and Port: 389 for StartTLS or no encryption, 636 for TLS
(LDAPS). The port follows the encryption unless you set another. A server
written as a URL, such as
ldaps://ldap.example.com:636, sets the encryption and the port from it. - Encryption: StartTLS checks the server's certificate against the system's trusted certificates, so a server with a self-signed one needs TLS (LDAPS), which Evolution Data Server connects to without that check.
- Search base: where in the directory people are, such as
ou=people,dc=example,dc=com. Search takes the whole tree under it or only its first level. - Sign in as: the entry to bind as, such as
cn=jane,ou=people,dc=example,dc=com, and its password. Leave both empty for a directory that can be searched anonymously. The password is kept in the keyring and handed to Evolution Data Server when the directory asks for it. A directory set up in Evolution with its password remembered needs none in Hylki: Evolution Data Server signs in with the one Evolution stored.
Saving checks the connection and says whether the directory answered, or why not (a password it refused, a server it could not reach or find, TLS that could not start). The check gives up after 30 seconds. A directory that fails during a search, such as one that needs a password neither Hylki nor Evolution has, says why under In Directories in Contacts, once in the status bar of each composer, and in its row in Settings → Contacts. It is left alone for 30 seconds before it is asked again. The console (the status bar with Settings → System → Console mode on) records each directory's answer to a search: how many entries it found and how many of them have an address, and Export log saves it. The Flatpak reaches the desktop's Evolution Data Server, which has to be installed on the system, as it is with GNOME.
A Microsoft 365 account signed in within Hylki can suggest people from the organization's directory as a recipient is typed, alongside LDAP directories. Turn on Search the organization directory under Microsoft 365 in the account's settings, where the account's other Microsoft Graph switches are too. Microsoft then asks to approve access to the directory (the People.Read and User.ReadBasic.All permissions). Where an organization lets only administrators approve apps, an administrator approves Hylki once, at the link shown. Accounts added through GNOME Online Accounts cannot use it, since GNOME holds their sign-in; add the account in Hylki with the Microsoft 365 / Outlook provider instead.
With Suggest only from this account on as well, a message written from that account is offered only the organization's directory and the people in the account's own mail. The directory's list includes the account's Outlook contacts. GNOME Contacts, LDAP directories and the other accounts' mail are left out, so a work account does not offer personal addresses.
Settings → Translation sets up a translation service you have an account with, under your own key:
| Service | What it needs | Notes |
|---|---|---|
| DeepL | an API key | A free key (ending in :fx) covers 500,000 characters a month. |
| Google Cloud Translation | an API key | The Basic (v2) API; the project needs billing turned on, even for the free allowance. |
| Microsoft Translator | a key, and the resource's region | Leave the region empty for a global resource. |
| LibreTranslate | the server's address, and a key if it asks for one | Can run on your own computer or network, so messages never leave it. |
Check the settings translates a greeting to show that the service answers. Translate into is Hylki's own language unless another is chosen.
A message is translated from the A文 button in its card's actions, or from Translate in its right-click menu. The card then shows the translation, with a banner naming the service and the language it came from, and Show Original in the banner or the menu switches back. The subject is translated with it, in the heading above the message. A translation is kept for the rest of the session, so opening the message again costs nothing more.
What is sent is the message's text, a paragraph or a cell at a time, with the bold, italics and links inside it but none of the sender's styling, images or link addresses. The translation is put back where the text was, so the message keeps its design; a plain-text message is shown as Reader View shows it. Long messages go in pieces, and one with over about 120,000 characters to send is not sent. Messages that arrived encrypted are never sent.
With Offer to translate on, a message in a language other than the one translations go into shows a Translate button above it. Which language a message is in is worked out on this computer; nothing is sent until the button is pressed.
In the composer, the A文 button beside the format chooser translates what you are writing: the selection if there is one, otherwise everything you wrote above the quote and signature, which are left as they are. It offers the language of the message you are answering first, recognised offline, then the one you used last, then every other. When everything is translated, the subject is too, unless the message is a reply or a forward, whose subject is already the conversation's. The translation replaces your text as one edit, so Ctrl+Z gives back what you wrote. Until you change the text again, the same menu offers Show Original, which puts back what you wrote, subject included, and then Show Translation. It works in rich text, plain text, Markdown and HTML. A message set to be encrypted is never sent for translation.
The settings are in translation.toml; the key is in the keyring.
An account's signature is written in the Signatures group of its settings, in the same editor as a message; Import File… loads one from an HTML or text file. Edit HTML, at the end of the editor's toolbar, shows the signature as its HTML source to edit in place, and Preview turns it back into the formatted signature. Scripts and style sheets are removed from the source; inline styles, tables and pictures are kept.
Add Signature starts another, for writing in another language or a shorter one for quick replies. Once there are two, a Signature chooser picks the one being edited and a Name field names it. Start messages with this signature marks the one new messages, replies and forwards open with; with it off for all of them, a message opens without one. A signature left empty is not saved.
With more than one, the composer's Insert Signature button lists them by name, with No Signature at the end. The one picked replaces the signature in the message, in the same place; with none in the message, it goes where a signature goes. Changing From to another account puts in that account's own signature; an alias of the same account keeps the one picked.
A signature's Sender name replaces the account's name in From while that signature is in the message, so one mailbox can sign as different people (empty keeps the account's name). It applies to the account's own address only: an alias keeps its own name. The From row then shows even when the account has a single address.
In a reply or forward the account's signature is placed above the quoted message, so it closes what you wrote rather than what the other person did. Settings → Composing → Signature in replies moves it below the quoted message instead, the placement Hylki had before 1.38. The setting applies when a composer opens; a draft keeps its signature wherever it was saved.
The signature follows a blank line and nothing else. Settings → Composing →
Separator line above the signature puts the traditional -- line (two
dashes and a space) between them, as Hylki did before 1.42. Thunderbird,
Evolution and Mutt use that line to show the signature dimmed and to leave it
out when they quote your message; Gmail, Apple Mail and Outlook ignore it.
Edit as New leaves the signature out, since the copied message already has one. Insert Signature, the button beside Translate at the end of the formatting row, puts the From account's signature where the cursor is, on a line of its own; with several it lists them, as above. Right-click the button for Insert Before the Text or Insert After the Text, the top or the end of the message, with the signature last picked or else the default. A signature already in the message moves rather than doubling; one inside a quoted message is left alone. The button is there only for an account that has a signature.
A reply or a forward opens in the reading pane, beside the message it answers. Settings → Composing → Reply and forward in the main window, switched off, opens them in a window of their own instead, as Compose in the main window does for a new message.
A reply opens with a line above the quoted message, "On Oct 25, 2026 at
14:03, Ada wrote:" in the app's language. Settings → Composing → Reply
Header changes it: {name}, {address}, {date} and {time} are
filled in from the original, so {name} <{address}> wrote on {date}: gives
"Ada ada@example.org wrote on Oct 25, 2026:". The date and time follow
Date format and Clock in Settings → Date and Time. The button at
the end of the row restores the default, which follows the language of the
app. A forward opens with the original's From, Date and Subject, in the
app's language too.
The quoted message keeps its layout: its colors, fonts, tables and the pictures it carries inside itself look as they do in the reader, and go to the recipient that way. Pictures on the sender's server show only when the reader shows them for that message, so answering a message does not load anything reading it did not. The recipient still gets them. In dark mode a quoted message that sets its own colors keeps the light ground it was designed for.
The quoted message opens folded behind a ••• button, since the reading pane beside the composer shows it already. A click shows it, with the button moved above it to fold it again. It is sent either way. A delete that would reach the folded quote, such as Select All and Delete, opens it instead of removing text that cannot be seen; the next one removes it. Markdown and HTML source show the quote as source. Settings → Composing → Fold quoted text, on by default, switched off, opens every quote in full.
A message that was replied to shows a reply arrow in the message list, one
that was forwarded a forward arrow, and one that was both shows both. A
conversation's row shows them for its newest message in the folder. The
arrows are kept on the server, so a message answered from another client
shows them too. The arrow appears as soon as a reply or forward is sent,
and goes again if the send is undone or fails; a message that waits in the
Outbox, or is sent later, marks its original when it goes. IMAP keeps them as the \Answered flag and the $Forwarded keyword,
JMAP as $answered and $forwarded, and POP3 in Hylki only. Microsoft 365
keeps only the last thing done to a message, as Outlook shows it, so a
message replied to and then forwarded there shows the forward arrow alone.
Mail already downloaded shows its arrows once it is fetched again.
A copy of a sent reply goes with the rest of sent mail unless the account says otherwise. In Mail Accounts → Edit → Special Folders, Save a copy of replies in has two other choices:
- Folder of the original files the copy of a reply in the folder of the message it answers, so a conversation kept in a project folder keeps your side of it there too. A reply to mail in the Inbox is filed in the Inbox.
- Folder of the original, not the Inbox does the same, but a reply to mail in the Inbox goes with sent mail.
The folder is the one the original is in when the reply is sent, so a message moved while you were writing is followed. A reply goes with sent mail when the original is in Sent, Drafts, Templates, Trash or Junk, when it is no longer in the account, when it is in another account than the one the reply is sent from, and when the folder will not take the copy. On Gmail, a message under a label is answered into that label, not into All Mail. Forwards and new messages are not affected.
It applies to IMAP and JMAP accounts. Microsoft 365 files its own copy in Sent Items, POP3 has no folders to file it in, and with Server saves its own copy of sent mail on, the server's copy is the only one.
A message being written is saved to the Drafts folder on its own every 30 seconds while it changes, so a crash or a lost connection costs at most that much. Nothing is saved before you have changed anything, so an untouched reply leaves no draft. Each save replaces the one before, and Save Draft, Send and Send Later replace or remove it as they would a draft you saved. Discard on a new message removes the copy it left; on a draft you had saved before, the last automatic save stays. A save that fails, offline say, is tried again at the next one, without a message about it.
A message sent waits five seconds before it goes, with Undo on offer in a notice at the foot of the window. Esc does the same as Undo (the most recent message, when several wait), unless a text field or a composer has the focus. Undo brings it back to the composer it was written in: a reply to the split beside its conversation, if that conversation is still open, anything else to a window. If it cannot be sent, the status bar says why. Settings → Composing → Undo Send sets the wait to 3, 5, 10, 20 or 30 seconds, or Off to send at once. Send Later does not wait: a scheduled message can be edited or removed in the Outbox until its time.
While it waits and while it is being sent, the message is listed in the Outbox, where Edit and Delete bring it back to the composer and Send sends it without waiting. Quitting Hylki before the wait is over keeps it in the Outbox, and it is sent at the next start.
When what you wrote mentions an attachment and nothing is attached, Send asks first: Send Anyway sends the message as it is, and Cancel, the default, goes back to it. The quoted original of a reply or forward and the signature are not looked at, and a file uploaded to the cloud or a picture put in the text counts as an attachment.
Settings → Composing → Attachment Reminder lists the words looked for, separated by commas. A word in the message counts when it starts with one of them, whatever its case: "attach" covers "attached" and "attachment", "allegat" covers "allegato" and "allegati". The default list covers the languages Hylki is translated into; the button beside the list puts it back. An empty list never asks.
Snooze puts a message away until a time you choose, then moves it back to the folder it came from, unread. It is on the reader's toolbar, in a message's right-click menu, and on z with single-key shortcuts (b with Gmail's keys). The menu offers this evening, tomorrow morning and afternoon, Saturday and Monday morning, and Pick a date and time… for any other. A conversation's row snoozes the conversation, as much of it as is in that folder; a card picked in the reader snoozes that message alone.
The message waits in the account's Snoozed folder on the server, so a phone or another mail program sees it leave the Inbox too. The folder is made the first time something is snoozed; on Gmail it is a label. In the Snoozed folder each message shows when it comes back in place of its date. A time chosen there replaces the old one, and Unsnooze brings the message back now. While any account's Snoozed folder holds mail, a Snoozed row in the unified section lists it all together; Settings → Sidebar → Unified → Snoozed turns it off. The folders are counted each time Hylki checks for new mail, so mail snoozed on another computer brings the row too. A reply that arrives in the conversation brings it back early. Undo (Ctrl+Z) right after a snooze puts the message back where it was.
The times are kept on this computer, in snoozed.toml, and Hylki moves the
mail back itself: snoozed mail comes back while Hylki is running, or as soon
as it starts after its time. Hylki on another computer does not know the
time, and leaves the message in the Snoozed folder; Unsnooze there moves
it to the Inbox.
A folder called Snoozed, at the top of the account or under the Inbox, is taken for the role. Any other is chosen in the account's Special Folders, under Snoozed. Drafts and templates cannot be snoozed, and neither can mail on a POP3 account, which has no folder to keep it in.
A template is a message kept to start new ones from. It lives in the account's Templates folder, on the server, so another client that keeps templates there, Thunderbird among them, sees the same ones.
- Save as Template, in the arrow beside Save Draft, keeps a copy of the message being written in Templates and leaves the composer open. The copy answers nothing: it carries no reply headers, and a message started from it begins a conversation of its own. An account with no Templates folder gets one the first time.
- A template opened in the Templates folder has a banner. Use Template, or a double-click on it in the list, opens a new message with its recipients, subject, text and files, sent from the address it was saved with. The template stays as it is.
- Edit Template opens the template itself, where a new message opens: in the reading pane, or in a window of its own with Settings → Composing → Compose in the main window switched off. Save Template puts the changed one back in its place, and nothing is saved on its own while it is open. Sending from it leaves the template in Templates.
- New Message from Template…, in the arrow at the end of New Message (on its right-click menu when the sidebar is folded to icons), or Ctrl+Shift+N, lists every account's templates to start from.
- Insert Template, in the composer's formatting row, puts a template's text into the message being written, where the cursor is. The recipients, the subject and the quoted original stay, so a reply can use a standard answer. The template's own signature is left out.
A folder called Templates is taken for the role, at the top of the account or directly under the Inbox. Nothing on a server marks one otherwise, so a folder by another name, "Vorlagen" say, is chosen in the account's Special Folders, under Templates.
Mail Merge…, in the menu beside Send, sends the message being
written once to each row of a CSV file, or to each member of a contact
group. A field written as {{Field}} anywhere in To, Cc, Bcc, Reply-To,
the subject or the text is replaced by that row's value:
Dear {{First Name}},
Your order {{Order}} has shipped.
The first row of the file names the fields. A field is matched to it by its
letters and digits alone, in any case, so {{first name}} and
{{first_name}} find a column called "First Name", and {{E-mail}} one
called "Email".
The file may be separated by commas, semicolons or tabs, as spreadsheets in
different languages save it, and be in UTF-8, UTF-16 or Windows-1252. A
contact group has the fields Name, First Name, Last Name and
Email.
Fields need not be typed. The braces button at the end of the To and Subject rows, the same button in the body's toolbar, or Ctrl+Shift+M opens a list of fields at the cursor, and a click puts one in where the cursor was: the shortcut picks To or the Subject when the cursor is in it, the body otherwise. The list has the columns of the CSV file chosen last, under its name, and a contact group's fields. For To it has only the fields that hold addresses, and the field goes in as a pill marked with the braces. Address suggestions stay closed while a field is typed there.
A draft or template keeps its fields, those in To, Cc and Bcc
too, so a merge can be saved and used again. Another mail app shows a field
there as an address at hylki.invalid, which reaches no one. Send
refuses a field in To, Cc or Bcc and points to Mail Merge…. Choose a CSV File… at its end picks another
file, which the Mail Merge… dialog then starts from too.
With To left empty, each message goes to the column whose values are email
addresses. To name the recipient too, write To yourself, for instance
{{First Name}} {{Last Name}} <{{Email}}>. Whatever is in Cc and Bcc goes
on every message.
The dialog lists the file's fields and steps through a preview of each message, filled in. A field the message names that the file or group does not have, a misspelled one or Company with a contact group say, is listed with where it is written, and Send stays off until it is taken out of the message or Leave these fields empty is switched on. A row without a valid address is left out and counted. Send then sends them all, one after another, from the From address chosen, each with its own copy in Sent. There is no Undo Send for a merge: the preview is the time to check. A toast counts the messages as they go, and its Stop sends no more of them. A message that cannot go waits in the Outbox, with the reason, and that includes one the server refuses, a mistyped address or a sending limit reached, which in an ordinary message comes back in a composer. When some did not go, the last toast has Show Outbox.
Limit sending rate, at the foot of the dialog, sends at most a set number of messages a minute or an hour, for a provider that limits how fast mail may go out, and says how long the merge will take at that rate. The choice is kept for the next merge. Quitting before a merge is done puts the messages not yet sent in the Outbox, each scheduled at the rate if one is set, and the next launch sends them from there. An encrypted message cannot be merged, since each recipient would need their own key.
Each address in To, Cc and Bcc is a pill, with its name when it has one and the address under the pointer. A space after a whole address, Return or a comma makes the pill, and the comma is not kept. A space after a name does not, so a name can still be typed to find someone in the suggestions. Addresses pasted as a list, separated by commas, semicolons or line breaks, become a pill each.
Backspace on an empty field turns the last pill back into text to edit, until the next space, Return or comma. A double click does the same for any pill, and its × removes it. A pill that is not an email address is red.
Pills are selected as files are: a click selects one, Ctrl+click adds one to the selection or takes it out, and Shift+click selects the pills between. Dragging the pointer over pills from beside them, or from the empty text after them, selects them as dragging over text does, and Ctrl adds them to the selection. A selection can take pills from To, Cc and Bcc at once.
The selection can be dragged to another place in its field, or into another field. While it is dragged, Cc and Bcc show if they were hidden, and a line marks where it will go; a field it was not dropped in hides again. The right-click menu moves the selection to the end of another field, edits a single pill, or removes the selection.
From the keyboard, Left at the start of a field selects the last pill, and Ctrl+A on an empty field selects them all. On a selected pill, Left and Right select the next one, with Shift to extend the selection, and Right past the last goes back to the text. Delete or Backspace removes the selection, Return edits the pill, and Menu or Shift+F10 opens the menu. Tab passes over the pills to the next field.
The From row lists each account's address and the aliases set up for it.
Its pencil turns the row into text, where any name and address can be typed
for this one message, a throwaway address or a +tag one, without making
it an alias; the arrow beside it goes back to the list. The message still
goes through the account picked in the list, and with one address that row
appears under More. A reply to mail sent to a +tag address of one of
your addresses starts from that address, and a draft saved from a typed
address opens with it. Whether the server accepts mail from an address it
does not know is up to the server: many refuse it, or rewrite it.
Several aliases can share one address under different names, such as a manager and a director writing from one shared mailbox, and the account's own address can have more names the same way. Mail from a shared address goes through the account's own SMTP server: an alias with its own server needs an address of its own.
A JMAP account lists the identities the server keeps for it as well, so an
alias made in the webmail is in the From row without setting it up again.
The message is sent as the identity with its address, or as a catch-all
identity for its domain (*@example.org) when there is one. The account's
page in Settings shows them under Send-as aliases, read-only: they are
changed where the server keeps them.
In the rich text editor Return starts a new line in the same paragraph, and Shift+Return ends the paragraph with a hard return, which leaves a space before the next one. Settings → Composing → Return starts a new paragraph swaps the two. In a list Return still starts the next item, and pressed twice in a quote it still leaves the quote. The setting applies when a composer opens. Markdown, HTML and plain text are written as source, where Return is always a new line.
The rich text editor's toolbar has bold, italic, underline, strikethrough, bulleted and numbered lists, quote, link and Clear formatting, all of which survive a switch to Markdown. The chevron after them shows or hides the rest of what a mail can carry:
- Paragraph style: Normal, Heading 1 to 3 and Preformatted. The menu's label names the style the cursor is in.
- Font: Sans Serif, Serif or Monospace, which leave the recipient's client to pick its own font of each kind; the fonts most mail programs offer, such as Arial, Georgia, Verdana and Courier New, each with a fallback; or Other Font… for any font installed here, followed by its generic kind in case the recipient lacks it. Each font in the menu is shown in its own face. The last five fonts picked with Other Font… are listed at the foot of the menu. With nothing selected, the font applies to what is typed next.
- Font size: points from 8 to 36, or Default. With nothing selected, the size applies to what is typed next.
- Text color and Highlight: the GNOME palette and Custom… for any other color, plus Automatic and No highlight to take the color off again. Each button shows the color it last applied.
- Decrease and Increase indent. In a list, Increase indent nests the item under the one above it.
- Insert emoji (also Ctrl+.) and Insert picture, which puts pictures in the message at the cursor, as dropping or pasting them does.
Colors, fonts and sizes go out as inline styles, which every mail client keeps. Markdown has no words for them, so switching such a message to Markdown or plain text leaves them out. Settings → Composing → Formatting toolbar says whether a new message starts with these tools shown (Always expanded) or hidden behind the chevron (Always collapsed, the default); the chevron changes it for the message at hand. Settings → Composing → Font and Font size set the font and size a rich-text message starts in, and they are sent with it, so the recipient sees them too. They cover what you write: the signature and the message quoted in a reply or forward keep their own look, and text given its own font or size in the message keeps it. Other Font… in the Font list picks any installed font. Default, for both, leaves the recipient's own font and size in charge. Settings → Composing → Default zoom is the size the composer shows a new message at, on screen only: Same as reading pane zoom, the default, follows Settings → Reading → Default zoom. When the composer is narrow, the toolbar wraps onto a second row, the chevron staying beside the tools it shows wherever the row has room for it.
Settings → Composing → Check spelling as you type underlines misspelled words in the subject and the message body. Right-clicking a word in the body offers corrections.
Settings → Composing → Languages has a switch for the system language and one for each dictionary the app can see, and any number of them can be on. A word is underlined only when none of the chosen dictionaries knows it, so a message can mix languages. Switching a dictionary on switches the system language off, and switching the last one off switches it back on. The system language is the session's own, or the nearest dictionary to it.
The Spelling Language submenu at the bottom of the body's right-click menu has the same choices, ticked as they stand. A choice made there is saved as the setting and applies to every open composer at once.
A word added under Added words goes into the first chosen language's word list. The subject accepts it at once, and the message body after a restart.
Settings → Composing → Check grammar and style marks what the checker finds in what you write: a mistake with a wavy blue line, a matter of style with a dotted one. Right-clicking a mark shows what is wrong at the top of the menu, with the suggestions to put in its place and Ignore, which leaves that problem alone in every composer until the app is closed. A suggestion goes in as one edit, so Ctrl+Z takes it back.
The text is checked about a second after typing stops. The quoted message and the signature are left out. It works in rich text and plain text; a message written in Markdown or HTML is not checked.
Checker is what reads it. No checker ships with the app: the first two are downloaded with the Download button under it, once, and run on this computer, so nothing you write leaves it.
| Checker | Languages | Download | Notes |
|---|---|---|---|
| Harper | English | 14 MB | Fast and light. The one offered when every spelling language is English. |
| LanguageTool | Over 30 | 305 MB | LanguageTool and the Java runtime it needs. It starts when a composer opens, takes a few seconds to, uses about 1 GB of memory while it runs, and stops after 15 minutes without a check. |
| LanguageTool server | Over 30 | None | A server at an address, below. What you write is sent to it as you type. |
The downloads come from their publishers (Harper
from its GitHub releases, LanguageTool from
languagetool.org, the Eclipse Temurin Java runtime
from Adoptium's GitHub releases), and each is checked against the size and
SHA-256 the app expects before it is unpacked. They are kept in
~/.local/share/hylki/grammar/; Remove deletes them again.
LanguageTool server takes the server's address:
| Server | Address | Notes |
|---|---|---|
| Your own | http://localhost:8081, or wherever it runs |
Nothing leaves the computer or the network it runs on. |
| LanguageTool's free service | https://api.languagetool.org |
No account. About 20 checks a minute, and 20,000 characters each. |
| LanguageTool Premium | https://api.languagetoolplus.com |
Fill in Username with the account's email address, and API key with the key from the account page. |
A server of your own can be the LanguageTool server from languagetool.org, or a container image of it, for example:
podman run -d --name languagetool -p 127.0.0.1:8081:8010 docker.io/erikvl87/languagetoolCheck the settings sends a test sentence and names the server that answered. When checking fails while you write, right-clicking the body says why.
Each paragraph is checked in its own language, one of those chosen for spelling in Settings → Composing → Languages, recognised on this computer, so a message in French and English is checked as both. A paragraph too short to tell goes with the one before it. Harper leaves the paragraphs that are not in English alone. Misspelled words are left to the spell checker while it is on, so they are not marked twice.
The settings are in grammar.toml; the API key is in the keyring.
A message can be written in any of four formats, chosen in Settings → Composing → Write messages in for new messages and switched for any single message with the format button at the right-hand end of the composer's formatting row, which wears the icon of the format it is set to and lists the others, the current one in your accent colour:
- Rich text: the WYSIWYG editor with its formatting toolbar. The default. It is sent as HTML with a plain-text alternative, not as RTF.
- Markdown: you write Markdown, the recipient gets formatted mail.
- HTML source: you write the message's HTML by hand.
- Plain text: no formatting at all, sent as
text/plainonly.
Markdown and HTML source are written as source: a monospace field, the formatting buttons gone from the row above it (they would go nowhere), and a Preview toggle beside the format chooser that swaps the source for the message as it will be sent. Nothing is sent as source. Markdown is rendered to HTML when the message goes out, and the Markdown you wrote travels as the plain-text alternative, so a recipient whose client shows plain text gets something that still reads as itself. Hand-written HTML gets a readable plain-text alternative made for it the same way.
Switching format converts what is already in the message, so you can start a
reply in rich text and finish it in Markdown; the quoted original comes
across as > lines.
Settings → Composing → Reply in the original's format, off by default,
answers plain text in kind. A reply, a reply to all or a forward of a message
that came as plain text only, the way mailing lists and many of the people on
them send it, opens in plain text, the original quoted as > lines that keep
its indents. A message with an HTML part is answered in the format chosen in
Write messages in. Drafts, templates and Edit as New open as they
always have, and the format button still switches any one message.
The Markdown Hylki understands is the dialect documented at markdownguide.org: all of the basic syntax, and all of the extended syntax:
| Basic | headings (both styles), bold, italic, blockquotes, ordered and unordered lists, code, horizontal rules, links (inline, reference and autolinks), images, hard line breaks, backslash escapes |
| Extended | tables with alignment, fenced code blocks with a language, footnotes, heading IDs ({#id}), definition lists, ~~strikethrough~~, task lists, :emoji: shortcodes, ==highlighting==, ~subscript~ and ^superscript^, and bare URLs and email addresses turned into links |
Two notes on what that means in mail. The HTML Hylki writes carries its
styling as style attributes on the tags themselves, because a <style>
block is the first thing most webmail clients throw away, so tables really
do arrive with their borders. And anything you send, in Markdown or in HTML,
passes through a sanitizer on the way out: scripts, event handlers and style
sheets are removed, while tables, inline styles, images and everything
Markdown produces are kept. That is not a defence against you; it is a
defence for you, since a <script> in a message is at best stripped by the
recipient's client and at worst the reason the message lands in their spam
folder.
A draft saved from a Markdown or HTML message is stored as ordinary mail (a formatted part and a plain-text one), so re-opening it puts you in your default format. Switching that draft back to Markdown converts it, which for a message that started life as Markdown lands very close to what you wrote.
An AI agent, such as Claude Code or Codex, can work with your mail through the Model Context Protocol while Hylki runs. It is off until you turn it on in Settings → MCP, and then nothing is shared until you share it.
Connecting. Copy Command for the agent from that page and add it to the agent as a local (stdio) MCP server. In Claude Code:
claude mcp add hylki -- hylki --mcpThe command is written for the way your copy of Hylki is installed, so use the one on the page for a Flatpak or an AppImage. It connects to the running app through a socket only your user can open. With Hylki closed or the switch off, the agent is told so.
What can be shared. Each account has its own switch, off to start with. Once on, it has these, each on its own:
| Switch | What it allows | At first |
|---|---|---|
| See message lists | Senders, subjects, dates, previews and folders | On |
| Read message text | The text of a message, and searching it | On |
| Search on the mail server | Finds mail not downloaded yet, and needs Read message text | On |
| Read attachments | The files on a message; a PDF as its text, and pages without text as pictures | Off |
| Prepare messages | New messages, replies and forwards, opened for you to check | On |
| Mark as read or unread | Off | |
| Add and remove stars | Off | |
| Add and remove tags | Only tags you already have | Off |
| Move and archive | Within the account | Off |
| Move to Trash | Mail already in Trash stays there | Off |
| See open conversation | The conversation you have open, in the main window or a message window | Off |
| Read and edit open drafts | Messages agents prepared that are still open | Off |
| Include drafts you started | The same for messages you are writing, unsaved text included | Off |
Full access, above these, turns on all of them for that account, in every folder but Junk and Trash, folders you kept back included. Junk and Trash keep their own switches under Folders, and turning them on there works with Full access too. It can still move mail to Trash without seeing into it. It changes neither the last three switches in the table, which are about what you are doing right now, nor the contacts switches, nor what no setting allows, and your own choices come back when you turn it off.
Suggested changes. An agent allowed to edit a draft suggests a change, and nothing changes until you press Accept. New and removed words show over the text, and a bar above lists the recipients it adds or takes out, with Bcc and addresses outside your own domains marked. Your signature and any quoted message stay as they are. While a suggestion waits, the text is locked and Send asks you to answer it first. Accepting puts plain text in place of what you wrote, and the bar says so when that would remove formatting, links or pictures; Undo brings them back. An agent can suggest a change to one draft once every ten seconds. A draft that is encrypted, or that replies to or forwards encrypted mail, shows an agent only that it is there, and takes no suggestions.
Reset to Defaults, at the end of an account's list, puts its switches and folders back to the table above and turns Full access off. The account stays shared.
Everything but starting a new message and working on an open draft needs See message lists, since that is how a message is named. Folders on the same row keeps single folders back. Junk and Trash are kept back until you allow them, as mail in them is the most likely to carry instructions aimed at an agent.
An agent has two searches. One looks in what Hylki has downloaded, at once. The other sends the search words to the account's mail server, which can take up to a minute, and saves the headers of what it finds in Hylki's list. Neither reads folders that are kept back. On This Computer and POP3 have no server to ask.
Contacts has two switches of its own, off to start with: Address books and directories, and People in your mail. The second draws on every account, shared or not, because the addresses in your mail are kept together.
What no setting allows.
- Sending. A message an agent prepares opens in a composer, with a banner naming every recipient and setting apart Bcc and addresses outside your own domains. You check it and send it. While you are at work in Hylki it waits, with a toast and a notification, until you ask for it or leave the app. It saves to your Drafts folder meanwhile, as any composer does after 30 seconds.
- Erasing mail for good.
- Encrypted mail. An agent sees that a message is encrypted and who it is from, not its text or its files, and it cannot reply to it or forward it, even after you have opened it. Hylki never asks GnuPG on an agent's behalf.
- Reading or attaching files from your disk.
Keeping an eye on it. Recent Activity lists what agents did, refused calls included, with the program's name as it gives it. The list stays in memory and is gone when Hylki quits. What an agent changes is in Undo, as if you had done it. A switch you turn off holds from the agent's next call.
Limits to keep in mind. Mail is written by whoever sent it, and an agent can be misled by what it reads. Hylki removes text a message hides with inline styles before an agent sees it and tells the agent to treat mail as data, but this does not catch everything, such as text colored like its background. What you allow an agent to read can reach anything else that agent is allowed to do, which Hylki has no say over. Any program running as your user can use the connection while it is on: the name in Recent Activity is its own word.
Hylki can read OpenPGP-encrypted mail, check signatures, and sign and encrypt
what you send. It does this through GnuPG (gpg), the same program the
terminal command and other mail clients use, so your keys live in one place
(~/.gnupg) and every program on the computer sees the same keyring. Nothing
here needs a terminal.
What you need
- The Flatpak build carries GnuPG and is set up already. A source or RPM
install needs the
gnupg2package (on Fedora it is installed by default). - Hylki never stores a decrypted message on disk: an encrypted message is decrypted for the reading pane each time you open it, and its body and attachments are kept out of the cache.
1. Make a key for your address
Open Settings → OpenPGP. The top row says whether GnuPG was found. Under Your keys, click Generate…, pick the address the key is for, choose how long it lasts, and enter a passphrase twice. Hylki hands the passphrase to gpg over a pipe and does not keep it; from then on gpg asks for it when the key is used, and remembers it for a while (ten minutes by default, the normal gpg-agent behaviour). The key is a signing key with an encryption subkey, so it does both jobs.
If you already have a key, click Import… instead and pick the key file.
2. Give people your public key
Click the export button on your key's row and save the .asc file, then send
it to the people who should write to you encrypted, or upload it wherever your
provider publishes keys. The file holds only the public half; the secret half
never leaves your keyring.
3. Get other people's keys
Hylki needs a person's public key to encrypt to them and to check their signature. There are four ways to get one, none of which need a terminal:
- A signed message from someone whose key you don't have shows an amber shield beside their name. Click it and choose Fetch the sender's key. Hylki looks in the message itself first (many clients attach the key in an Autocrypt header), then asks the sender's provider (WKD), then the keyservers.
- A message with a key file attached shows an Import OpenPGP key button on that attachment.
- Under Settings → OpenPGP → Other people's keys, Fetch by address… looks a key up by email address, and Import… reads a key file.
- A key someone sends you by any other route can be imported the same way.
Other people's keys are listed by name. The search field above the list finds a key by name, address, key ID or fingerprint, and the menu beside it shows only the trusted keys, the ones not trusted yet, or the expired and revoked ones. These keys are left out of the Settings search.
4. Trust a key
An imported key checks signatures, but until you have vouched for it the shield stays amber and says the key is not trusted yet. Compare the key's fingerprint with the one its owner gives you in person, on their website or over another channel, then click Trust… on the key's row (or Trust this key… in the shield's popover). Hylki signs the key locally with your own, which is what turns the shield green. Trusting a key you have not checked lets an impostor's signature pass as theirs, so do check.
Trust covers the addresses the key has when you give it. If a trusted key later gains an address, its row offers Trust… again and the dialog names the new address, and mail signed from that address stays amber until then.
5. Send signed or encrypted mail
The composer has two buttons beside Send: Sign and Encrypt. Sign adds a signature others can check with your public key. Encrypt scrambles the message to every recipient's key and your own, and turns Sign on too. If a recipient has no key in your keyring, or your address has no key of its own, Hylki says so before anything is sent. Replying to an encrypted message starts with Encrypt on.
When a recipient's key is one you have not trusted yet (step 4), Send names them and asks first: anyone can publish a key with any address on it. Send Anyway encrypts to the key as it is and does not ask about that key again; it asks again if the address gets a different key. Those keys are listed under Settings → OpenPGP → Unchecked keys you encrypt to, where Ask Again takes the answer back. Removing a key does the same. With several keys for one address, the one you trusted is used.
Bcc recipients are encrypted to without their key IDs in the message, so the To and Cc recipients cannot tell whose keys were Bcc'd. They can still see that some were. gpg tries each secret key a recipient has on a hidden key ID, so someone with several passphrase-protected keys may be asked for more than one.
An encrypted message carries its subject inside, where only the recipients
can read it, and "..." as the subject anyone else sees, as Thunderbird does.
Hylki and other mail programs that read subjects from there show the real one
once the message is decrypted. For recipients whose mail program shows only
"...", turn off Hide the subject of encrypted mail under the account's
OpenPGP group; that account's encrypted mail then goes with its subject
readable outside. Stored on the account as plain_subject = true in
accounts.toml. The message list shows "..." for encrypted
mail, because nothing decrypted is kept between visits; the reader, a message
window and a printout show the subject inside.
Each account uses the key whose address matches. To use another key for an account, open the account in Settings → Mail Accounts and choose it under OpenPGP.
To sign everything an account sends, turn on Sign messages by default
under the same OpenPGP group. New messages, replies and forwards from that
account then open with Sign on, and a reopened draft does too. Changing From
in the composer moves Sign to the new account's setting until you press Sign
yourself; after that the composer leaves it as you set it. Stored on the
account as sign_by_default = true in accounts.toml.
Reading the result
Beside a sender's name, a lock means the message was encrypted and a shield means it was signed. Green: everything checks out against a trusted key. Amber: a doubt, such as an unknown or untrusted key, or an expired one. Red: a failure, such as a signature that does not match or a message that could not be decrypted. Click the icon for the details.
A signature only shows who owns the key, so it stays amber when none of the key's addresses is the message's From address, however much the key is trusted: it reads Signed by another address, and the details say which address the key lacks.
To have the result in words as well, switch on Settings → Reading → Name the OpenPGP result. The icons then sit in a label that reads Signed, Encrypted, Encrypted and signed, or what is wrong, such as Bad signature or Signed, unknown key.
If something goes wrong
- GnuPG was not found: install the
gnupg2package. - No passphrase prompt appears when you expect one: gpg-agent remembers a
passphrase for a while after you type it.
gpg-connect-agent reloadagent /byeclears it, or shortendefault-cache-ttlin~/.gnupg/gpg-agent.conf. - Could not be decrypted: the message was encrypted to a key you do not have. Ask the sender to use the public key you exported in step 2.
- Nothing to encrypt with for an address: that person's key is missing; see step 3.
Files dragged from a file manager over a composer bring up a card for each place they can go, and the files go where they are let go:
- Attach sends them with the message.
- Insert in Text places the pictures in the message where the cursor is (at the top when the cursor is not in the text), and attaches any other file. It is offered when the files include a PNG, JPEG, GIF, WebP, BMP, SVG or AVIF picture of 32 MB or less, and only while the message is being written as rich text: plain text has nowhere to put a picture, and in Markdown or HTML the reference is yours to write.
- Upload to Cloud opens the upload dialog for the files, as the composer's cloud button does. It is offered when a cloud storage account is set up (see Cloud attachments).
Letting go between the cards attaches the files. A composer in a window of its own shows the cards too.
Dragged over the main window with no message being written in it, files bring up the same cards side by side, each starting a new message: Attach to New Message, Insert in New Message and Share Link in New Message, offered on the same terms (Insert in New Message when new messages start as rich text, in Settings → Composing → Write messages in). Attach to New Message asks about files over the size limit the way Send with Hylki does (below). While a message is being written in the main window, files dropped anywhere else in it go into that message. Folders are skipped.
Select files in GNOME Files (Nautilus), right-click, Send with Hylki: a new message opens with them attached. The entry comes from a small extension that Files loads, so it has to live outside the app, in your home folder.
What you need
- The
nautilus-pythonbindings, which let Files load extensions written in Python:sudo dnf install nautilus-pythonon Fedora,sudo apt install python3-nautiluson Debian and Ubuntu,sudo pacman -S python-nautiluson Arch. - Hylki 1.29 or newer, Flatpak or native.
Installing it
Open Settings → System → GNOME Files and click Install. Hylki writes
the extension to ~/.local/share/nautilus-python/extensions/hylki-nautilus.py
and shows whether the installed copy is this version's. Then click
Restart (or run nautilus -q): Files closes its windows, and the next one
opens with the entry. Once Files has loaded the extension the row says so; if
it still says "not loaded" after a restart, the nautilus-python package is
the usual reason (a native install of Hylki checks for it and tells you; the
Flatpak cannot see the host's packages). Until Files has loaded the extension,
the group also shows the install command for your distribution, with a copy
button. Remove takes it out again the same way.
Without the app, the same file is in the repository at
data/nautilus/hylki-nautilus.py:
mkdir -p ~/.local/share/nautilus-python/extensions
curl -fsSL -o ~/.local/share/nautilus-python/extensions/hylki-nautilus.py \
https://raw.githubusercontent.com/hyprlab/hylki/main/data/nautilus/hylki-nautilus.py
nautilus -qThe extension launches Hylki by its desktop id (co.hyprlab.Hylki, then the
beta's), so it works whichever way Hylki is installed. Folders are skipped;
files on a mounted share reach the app through their mount path.
Files also has its own Email… entry, which sends the selection to whatever
app handles mailto: links; if that is Hylki, it does the same thing without
the extension.
What the files go into
When the files arrive, Hylki asks what they are for: a new message, a draft you pick from a list of every account's drafts, or a reply to a message you pick (the one you are reading comes first; a search box narrows the list by sender, subject or account). Files that together exceed the size limit (20 MB by default) bring a second question when a cloud storage account is set up: attach them anyway, or upload them and put download links in the message instead. Each dialog has an Always do this box, and Settings → System → GNOME Files holds the same choices, so the questions can be skipped: what the files go into, what happens over the limit, and the limit itself.
When a reply ends with the message it answers, the reader folds that part
away behind a ••• button. It recognises the quotes Gmail, Outlook (web and
desktop), Apple Mail, Thunderbird, Yahoo and Hylki write, an "On … wrote:"
line before them, an "Original Message" divider, and the > lines of
plain-text mail. Once opened, the button sits where the quote begins and
folds it again. Nothing is folded when your reply comes after or between
quoted lines, so an answer written inline always shows in full.
A click on a message's header in a conversation folds it to a short card: a line with the sender's circle and name, then a star, a paper plane or an inbox for sent or received, a paperclip when it has files, and the day. Under it comes the start of the message, in as many lines as Settings → Message List → Preview lines asks for; the subject is the conversation's, in the heading above. A click on the card opens it again; a double-click on the header still opens the message in a window of its own. A click anywhere else on a message, its text included, selects it, and the action keys act on it. Ctrl and a click add a message to the selection or take it out, and Shift and a click select every message from the first selected to that one, without folding or opening it. Archive, Delete, Spam and Move act on the selected messages alone, and the rest of the conversation stays open.
A message's header, or its folded card, drags it to a folder in the sidebar, as its row in the message list does; with several selected, the drag carries all of them. A drag across the message's text selects the text.
Settings → Conversations → Fold earlier messages decides how a
conversation opens: Never shows every message, Messages already read
folds what you have read, and All but the newest folds every message
except the newest, read or not. The newest always opens, and so does a
message you move to with w or b. Right-clicking anywhere in a
conversation offers Expand All Messages and Collapse All Messages.
What you fold or open stays that way while the conversation is on screen,
and so does a message read while it is open.
Printing shows every message in full.
Ctrl+Shift+F or the main menu turns Focus Mode on and off. Settings → Focus Mode holds everything about it. While it is on, that page decides the layout, and the settings on the other pages for the same things wait until it ends: the sidebar and its unified rows and sections, the message list's layout, column headings, avatars, preview lines, subjects, stars and attachment icons, and Reader View. Favorites, Filters and Tags sit above the accounts, and Contacts and Attachments in the footer. What is changed from the window while it is on, such as folding the sidebar, lasts as long as it does. Unread counts off takes every unread count and dot out of the sidebar, on avatars and folders too. The Outbox keeps its count.
On a new install the message list uses the Automatic layout, with subjects, stars and attachment icons hidden. An existing Focus Mode setup is left as it is.
The toolbar is the one exception: with Fold the reading pane's toolbar off, the toolbar is as arranged in Settings → Appearance → Toolbar. Colors, fonts, dates and the columns of the single-line layout are the same in and out of Focus Mode.
The ⋯ at the end of a message's header opens the same menu as a right click on the message. It acts on that message, and has Show Sender's Fonts and Colors while Settings → Reading → Use my own font or Use my own colors is on.
The buttons above the message are in two groups. The left group, up to seven buttons, stays on the bar at every width: Reply, Reply All, Forward, Star, Archive, Spam and Delete by default. The right group folds into a ⋯ menu: always while Settings → Appearance → Always fold the right group into ⋯ is on, as it is on a new install, and otherwise only when the pane is too narrow for it. Settings → Appearance → Toolbar moves buttons between the groups, or out of the toolbar, by dragging them; right-clicking an empty part of the toolbar opens it there.
Double-clicking a message in the list, or a message's header in a conversation, opens it in a window of its own. Its toolbar is the reader's: the same buttons in the order Settings → Appearance → Toolbar gives them, and the right-hand group folds into a ⋯ menu as it does in the main window. Its files are in the attachment drawer under the message, and on each message's card when those are switched on, and images and PDFs open in the same full-window preview. A conversation's window gathers the files of every message in it. Its Reader View switch changes that window alone; the main window and the choice Hylki remembers stay as they were. Ctrl+F finds in the message and Ctrl+P prints it.
A message saved whole, as a .eml file or Outlook's .msg, opens in a
window of its own:
double-click it in GNOME Files (Hylki is offered for email files), pass it to
hylki on the command line, or pick Open Message File… in the command
palette (Ctrl+K). It is drawn as mail from a server is, with its
attachments in the drawer, and Reply, Reply All and Forward
write from the account in view. It belongs to no folder, so there is nothing
to star, move or delete.
Save as File…, in a message's right-click menu in the list or on its card,
saves the message whole, as the server keeps it, under its subject with
.eml on the end.
A .msg keeps the headers the mail server sent when Outlook has them, and
otherwise its sender, recipients, subject and date are read from the file.
Its HTML or plain text, its attachments and the pictures in its text all
come through. A message whose text Outlook kept only as RTF shows no text,
and a message attached to it is left out.
Settings → Reading → Message appearance draws every message light, dark or as the system is. The message header has a switch beside Reader View that draws the message on screen in the other scheme, for that message alone, until Hylki is closed. The switch starts off for every message; on draws the message opposite the theme. A message keeps the scheme chosen for it when the theme changes afterwards, and the switch then reads off if the message matches the new theme. In a conversation the choice follows the message the conversation was opened on. It works in a message's own window too. Light / Dark Mode switch, in the same group, hides the switch.
Above the subject, the message header names the account the message is in,
in the account's color. Settings → Reading → Show account in message
header hides it, in the main window and in a message's own window. It is
stored as account_chip in privacy.toml.
Ctrl+F with the message focused, or the magnifier in the reader's toolbar, opens a find bar for the message or conversation shown. Enter and the arrows step through the matches. Esc, Ctrl+F again or the close button puts the bar away and hands the keyboard back to the message, so the next Ctrl+F finds in it again. Settings → Reading → Find bar position opens the bar at the top of the message, the default, or at the bottom, where it leaves the message where it is. A message in its own window follows the same setting.
Ctrl+P prints the message or conversation in the reader, and Ctrl+Shift+P, the printer button in the reader's toolbar or Print Preview in the message's right-click menu shows it first, page by page, as it will come out. The preview prints from its Print… button and saves a PDF from Save as PDF…. A message opened in a window of its own has the same printer button, menu entries and keys.
The printed page starts with the subject, sender, recipients and date, and has a 15 mm margin on every side. Settings → Reading → Printing adds to it:
- Page numbers, on by default: "Page 2 of 5" at the foot of every page.
- Date printed: the date and time of printing at the foot of every page, at the left.
- Wider left margin: 25 mm at the left, so punched holes miss the text.
The preview is laid out on the paper chosen the last time you printed, or your language's default paper size before that.
Create Event… and Create Task… in a message's right-click menu, in the list or the reader, open a dialog filled in from the message: its subject as the title, and its sender, date and text as the notes. An event starts at the next whole hour and lasts an hour, or takes whole days with All day. Alarm and Second alarm each go off at the start or from five minutes to a week before, and the ones picked last are picked again; a task has no due date until Due is switched on.
The event or task is written to the calendar or task list chosen in the dialog, from those in GNOME Online Accounts, Evolution or GNOME Calendar (Evolution Data Server). Events show up in GNOME Calendar, Evolution and the clock menu's agenda; tasks in Endeavour and Evolution. Calendars that only read, such as Birthdays & Anniversaries, are not offered, nor is the Reminders list iCloud shows with a warning sign: Apple serves upgraded reminders over no calendar protocol, so a task written there never reaches the Reminders app. The last calendar and task list used are chosen first the next time. Each is listed under its account's name in Settings → Contacts, else the nickname of the mail account with the same address, else the address.
On a desktop without Evolution Data Server the dialog's button is Open in
Calendar: the event or task is handed as an .ics file to the application
that opens calendar files, as an invitation's Add to Calendar is.
Main menu → Reading Pane puts the reader Right of the list, Below it or Off; Ctrl+Alt+1, Ctrl+Alt+2 and Ctrl+Alt+3 do the same. Below or off, the window's close button moves to the list's header, and replies, forwards and new messages open in a window of their own. Below, the toolbar stays at the top of the reader; drag the line between the list and the reader to set the list's height, which Hylki remembers apart from its width beside the reader, and the attachments start folded.
Off, the list takes the whole window and the toolbar moves to its header, at the top of the window. It folds into its ⋯ menu there as it does in the reader, and gives way to the selection bar while several rows are selected. Find, which searches the reader, is left out; Print prints the selected message, or its whole conversation. Clicking a row selects it and nothing more: the keys, the right-click menu and the selection bar act on it, but it stays unread. A double-click, Enter or, with Gmail's keys, o opens it in a window of its own (see A message in its own window), which marks it read as Settings → Reading → Mark as read says. A conversation opens whole, each message marked as its window scrolls through it. Hylki remembers the choice.
Settings → Message List → Layout sets how the list shows a message. Cards gives the sender, the subject and the start of the text lines of their own. Single line puts them on one line in columns: the sender's circle and name, the subject with the text dimmed after it, then tags, a paperclip, the conversation's size and a short date. Automatic uses one line while the list pane is dragged wider than about 600 pixels and cards when it is narrower, and always one line with the reader below the list or off. A new install starts on Automatic; an existing choice is kept. On one line a row does not swipe, as sideways is how the list scrolls to its columns; the right-click menu and keyboard shortcuts do the same things.
Settings → Message List → Columns chooses what a single line shows and in what order: drag a column between Shown and Not shown, or along the row. Any number of columns can be shown. The subject always stays, and the conversation's size rides at its end. The columns are:
| Column | What it shows |
|---|---|
| Star | The star, lit when the message is starred |
| Replied | An arrow when the message was replied to, another when it was forwarded |
| Sender | Who it is from; in Sent, who it went to |
| Recipients | Who it went to |
| Correspondents | Everyone who wrote in the conversation, newest first, you as "me" |
| Subject | The subject, with the start of the text dimmed after it |
| Tags | The message's tags |
| Attachment | A paperclip when there are files attached |
| Importance | A red mark for high importance, a grey arrow for low |
| Account | The account the message is in |
| Due Date | When a Microsoft 365 follow-up flag falls due, red once it has passed |
| Date | When it arrived |
Importance comes from the X-Priority, Importance and Priority
headers, or from Microsoft 365. Mail already downloaded shows as normal
until it is fetched again. Only Microsoft 365 has a due date, so Due Date
takes room only in a list that holds Microsoft 365 mail. Restore
Defaults goes back to star, replied, sender, subject, tags, attachment
and date.
Column headings, in the same group, names the columns above the list. Clicking a heading sorts the list by that column, and clicking it again reverses the order; the sorted heading is in the accent color, with an arrow. Correspondents sorts by the names the column shows, and Tags by tag name with untagged mail last. The sort menu follows the headings.
The name, tags and date columns are resized by dragging a heading's edge, where a line shows under the pointer: the right edge of a column left of the subject, the left edge of one right of it. A double click there puts the column back to its usual width, and Restore Defaults puts every column back.
Fit columns to the list, in the same group and on until it is switched off, narrows the name and tag columns in proportion when the list is too narrow for the widths set; the dates keep theirs. Switched off, every column keeps its width, the subject takes the room they leave, and a list too narrow for them all scrolls sideways to the columns past its edge, the headings with it.
A right-click on the headings offers Customize Columns…, which opens Settings at Message List → Columns.
Settings → Message List → Group by date, on by default, divides the list under headings: Today, Yesterday, Last 7 days, Last 14 days and Older, counted in calendar days on this computer's clock. The headings show only while the list is sorted by date, newest or oldest first, and move on at midnight. A conversation goes under the heading of the message that places it in the sort, the newest for newest first and the oldest for oldest first, and its replies stay with it when it is opened out. The headings work in both layouts and in search results, and are not rows: the keyboard, selection and swipes pass them by. It is off unless switched on.
Settings → Message List → Tint tagged messages washes the row of a tagged message with its tag's color, in both layouts. A message with more than one tag takes the color of the one listed first in Settings → Tags. A selected row keeps the selection color. It is on unless switched off.
Settings → Message List → Tags and labels under the text puts a card's tags, Gmail labels and folder pill on a line of their own under the message's text, so the subject keeps the row's full width. It is off unless switched on; a single-line list keeps them in its Tags column.
Settings → Message List → Keep the search field open shows the search field with the list all the time, instead of only after the search button, Ctrl+F or /. One click in it starts a search. Esc clears it and returns to the list, and it stays where it is. It is off unless switched on.
Settings → Message List → Search field position and Selection bar position set where the search field and the bar for several selected messages open: at the top of the list, the default, or at the bottom. At the top, each one pushes the messages down when it opens; at the bottom, the list gets shorter from its foot and the messages stay where they are. When both are on the same side, the search field is the outer one, so selecting messages never moves it.
The button beside the search field sets where a search looks, and the info button beside each choice in its popover says what that choice searches. All folders (except trash & junk) searches every folder of every account except Trash and Junk, unless the list is showing one of them. Everywhere takes in Trash and Junk too, and This folder only the folder on screen. A search started in an Inbox, or in All Inboxes, looks in all folders; one started anywhere else looks in that folder, and the button changes it for as long as the folder is open. In all folders and everywhere, each result wears a pill with the name of the folder it is in, and a Gmail message filed under several labels is one result: its Inbox copy, else a label's, else All Mail's. Folders not opened since Hylki started are searched from the index Hylki keeps of them, which covers mail archived to Gmail's All Mail.
Each word typed is looked for on its own, anywhere in the message and in any
order: rossi mario finds mail from Mario Rossi, and rossi invoice finds his
mail that mentions an invoice. Words in quotes, "mario rossi", are found as
written. A word is found in the subject, the sender, the recipients (To, Cc and
Bcc, by address or by the name the person goes by in your mail), the preview,
and the message's text:
- Mail on this computer: the text of every message whose body is on disk
(opened, fetched ahead, or kept offline, see
Storage) is indexed, and a word is found as the start of a word,
so
invofinds "invoice" while it is being typed. - Mail on the server: once typing pauses, each account's server is asked for the mail holding every word, in the folders the search covers, and what it finds joins the results. A spinner beside the search field shows while it answers. IMAP servers are searched a folder at a time (on Gmail, All Mail stands for every label), JMAP and Microsoft 365 servers in one request. Servers match whole words, and how a quoted phrase is matched is the server's own. POP3 has no server search; its mail is all on disk.
A few words narrow the search to one part of the message, and can be combined with each other and with plain words:
| Typed | Finds mail |
|---|---|
from:ann |
from a sender whose name or address holds "ann" |
to:lee |
sent to, or copied to, someone whose name or address holds "lee" |
subject:report |
with "report" in the subject |
in:archive |
filed in a folder whose name holds "archive", in any account, whatever the button beside the field says |
has:attachment |
with attachments |
is:unread, is:read, is:starred |
unread, read, or starred |
A value with spaces goes in quotes: from:"mario rossi". A colon in any other
word, such as 10:30 or re:, is searched for as written.
The sort and filter button in the list's header opens a popover of three columns. Sort by orders the list by date, newest or oldest first, by sender or subject, or puts unread or starred mail first. The order chosen there or by a column heading is kept for the open folder, from one launch to the next, and each folder, unified row, tag and smart folder has its own. One where none was chosen uses the default, newest first. Use for All Folders makes the open folder's order the default and drops the orders the others kept. Show only holds the quick filters:
- Unread and Starred
- Has Attachments
- Addressed to Me: one of your addresses or aliases is in To or Cc
- From Contacts: the sender is in your Contacts, as for filter rules
- High Importance
- Tagged: the message has a tag or a Gmail label
- Today: it arrived since midnight on this computer's clock
In Dates, the list shows only the mail that arrived from the start of the From day to the end of the To day, on this computer's clock. Choosing From or To sets it to the day in blue on the calendar below them, or moves the calendar to the day it already has; a click on a day then sets it. A click on a day with neither chosen sets From. An end left at Any Date is open, to show everything since, or up to, a day. Clear Dates opens both ends again. Older mail is there as soon as the folder's index has reached it.
A click turns a filter on or off and leaves the popover open, so an order and several filters can be set at once; together the filters show only the mail that matches all of them. While any is on the button is in the accent color and its tooltip names them, with the dates. Clear Filters turns them all off. They apply to whichever folder or search is shown, and last until Hylki is closed. In Focus Mode they are under Filter and Sort in the list's ⋯ menu; the dates are set in the popover only.
Clicking the unread dot on a row marks that message read without selecting or opening it. A conversation's dot that is lit only for an unread reply does not take the click.
The list puts its rows on screen a few hundred at a time as it is scrolled. Once the pointer reaches the scrollbar, the rest of the folder joins them, so the bar spans all of it, back to the oldest message. While the bar is dragged in a list sorted by date, a label beside it names the month and year of the rows in the middle of the view.
Settings → Appearance → Text size makes Hylki's text smaller or larger
than the desktop's, from 90% to 150%: the sidebar, the message list,
Settings and the text of messages. Icons keep their size. Default follows
the desktop's own text scaling. Stored as text_scale in privacy.toml.
Settings → Appearance → App icon puts one of five icons on the app's
launcher: the default, the same envelope on a blue, navy or yellow square,
or the classic icon. An icon set on the launcher some other way, with a menu
editor or by editing its .desktop file, is left alone when Hylki starts;
Settings says so above the gallery, and picking an icon there replaces it.
Hylki draws its icons, and those of the buttons, arrows and checkmarks GTK
draws for it, from copies built into the app, so it looks the same on every
desktop whatever icon theme is set. Settings → Appearance → Use the
desktop's icons draws them from the desktop's icon theme instead, with
Hylki's copies standing in for any icon the theme lacks. It applies at once
and is stored as desktop_icons in privacy.toml.
A folder's unread count is in the accent color. With Settings → Sidebar →
Highlight only new unread mail on, it is only while mail has come into the
folder since you last looked at it; once you have opened the folder, the
count turns grey, however much is still unread, until more arrives. A folder
on screen counts as looked at, and so do the inboxes of All Inboxes while it
is open. Reading mail elsewhere lowers the mark with the count. What was
unread when the setting was turned on counts as seen. The marks are kept in
state.toml, and the setting is seen_counts in privacy.toml.
Hylki puts a number on its icon in the dock or task manager. KDE Plasma's task manager shows it, and so do the Dash to Dock and Dash to Panel extensions for GNOME; GNOME's own dash has no badges. Settings → System → Unread count on the app icon chooses what it counts:
- All unread inbox mail, the default: every unread message in every account's inbox, the same count as the tray icon's dot.
- New since last in front: only the inbox mail that arrived while the main window was not the active window, and is still unread. It is the mail a new-mail notification is raised for, less what a filter filed out of the inbox, whether or not notifications are on. Reading or deleting one of those messages, from a notification's buttons or on another device, takes it off the count, and the count goes back to none as soon as the main window is in front. It starts from none each time Hylki starts. The tray icon's dot still counts every unread inbox message.
- Off: no number.
Stored as launcher_badge (off, all_unread or new_since_front) in
privacy.toml; launcher_count, the on/off switch it replaced, is still
written for older versions and read when launcher_badge is absent.
Settings → System → Renderer chooses how the windows are drawn:
Automatic (GTK's own choice, Vulkan where it works), Vulkan,
OpenGL or Software. On older graphics hardware where Vulkan support
is incomplete (Intel HD 4000 and its generation, for instance), OpenGL or
Software can draw more reliably. The choice applies the next time Hylki
starts. A GSK_RENDERER set for the session wins over it, so this still
works:
flatpak override --user --env=GSK_RENDERER=gl co.hyprlab.HylkiLeft on Automatic on X11, Hylki checks before GTK starts that the X
server can attach its shared memory, which Mesa's software driver needs on
a display without a GPU, such as Xvnc. When it cannot, Hylki draws with
Software, and the log says renderer: cairo, the X server cannot attach shared memory.
A message an organization has classified with Microsoft Purview, such as
Internal Use or Confidential, shows its label as a pill beside the sender's
name, with a tag icon. The label comes from the message's msip_labels
header, so it shows on any account, not only Microsoft 365. A tenant that
leaves the label's name out of the message shows the pill as Labeled.
Outlook's older Sensitivity setting (Personal, Private, Confidential) shows
the same way.
For a Microsoft 365 account signed in within Hylki, Show sensitivity label names, under Microsoft 365 in the account's settings, names those labels from the organization's own list, with the label's color on the tag icon and the organization's description of the label in the pill's tooltip. Turning it on asks Microsoft to approve reading the labels (the InformationProtectionPolicy.Read permission). The list is read once a session and again after an hour. It holds the labels published to you, so a label from another organization stays Labeled. As with the directory, an account added through GNOME Online Accounts cannot use it.
Hylki only shows the label: it does not apply the rules the organization attached to it, and it cannot set a label on a message you write. A message protected with encryption is a separate matter the label only names. Mail downloaded before Hylki read labels shows its label once it is downloaded again.
The Unsubscribe banner on mail from a list asks before it leaves the list, and can take the mail already received from that address to the Trash with it: tick Also delete the messages from … in that dialog.
Where a list offers one-click unsubscribe (RFC 8058), Hylki sends the request itself, with no page in between. It does so only over https, and only when the mail provider's DKIM check covers the List-Unsubscribe header or nothing about the sender looks wrong (no failed or suspicious sender check). Otherwise the list's unsubscribe page opens in the browser instead, so a forged message cannot have Hylki send a request in your name.
For the rest, each account's settings have Move list mail to Trash, under Syncing: Inbox mail with an unsubscribe link (a List-Unsubscribe header) that is older than 30, 60, 90 or 180 days goes to the Trash, checked at each sync and at most every six hours. Starred mail stays, and so does anything without the header, however old. It works for IMAP and JMAP accounts; Microsoft 365 offers no way to search for the header, so the choice is not shown there.
A message can ask for a read receipt: a short message back to its sender
saying when it was opened. When one asks, a banner above its text says so,
with Send Receipt and Ignore. Either answer is remembered, and on IMAP
and JMAP accounts the message is marked $MDNSent, as Thunderbird and K-9
Mail mark it, so other mail apps do not ask again. Your own mail, and mail in
Sent, Drafts, Templates, Junk and Trash, never asks. Neither does mail
downloaded before Hylki read the request.
Settings → Privacy → Send read receipts chooses Ask each time, Always or Never. Always sends the receipt when the message is shown, except when it would go to an address other than the one the mail came from (its Return-Path), or the message was not addressed to you in To or Cc: those still ask, as RFC 8098 requires. Never sends none and shows no banner.
The receipt goes from the address the message was sent to, with no copy in
Sent, as the multipart/report RFC 8098 describes: a sentence for the
person, and a report their mail app reads.
To ask for a receipt on a message you write, tick Request a read receipt in the menu beside Send. Settings → Composing → Request read receipts ticks it for every new message. Many mail apps send none, or only when the person agrees.
Sent mail that asked for a receipt shows two grey checkmarks beside its date, in the list and in the reader. They turn green when a receipt comes back, and pointing at them says who opened the message and when; for mail to several people, how many of them did. Hylki learns that a message asked for a receipt when it reads the copy in Sent, so mail sent from another app shows the marks once its Sent copy has been opened or fetched ahead.
A receipt that comes back is a message of its own. Once Hylki has read it, it
is marked read and moved out of the Inbox: Settings → Composing → Returned
receipts chooses Move to Trash, Archive or Keep in Inbox. A
receipt that is open in the reader is left where it is. Who read what is kept
on this computer, in read_by.toml, so another computer shows the marks only
for the receipts it reads itself. A receipt that says the message was deleted
unread does not turn the marks green, and stays in the Inbox.
A receipt that comes back also posts a desktop notification, "Read by" the person, with the message's subject; clicking it opens the message. Settings → General → Read receipts turns it off. With Show sender and subject off it says only that a receipt came back, and receipts more than a day old, read for the first time, post nothing.
The menu beside Send has Importance: High, Normal or Low.
High and low send the X-Priority and Importance headers most mail apps
read; normal mail goes with no header, as most mail apps send it. A draft or a message in the Outbox keeps its
importance when it is opened again; a reply starts at normal.
Mail the sender marked high shows a red mark beside its paperclip and star, and mail marked low a grey arrow, in the list's card layout and in its header in the reader. On a single line the Importance column shows it (see Message list layout), and the High Importance quick filter lists only mail marked high.
Messages and attachments that have been opened, or fetched ahead for the newest mail in each folder, are kept on the computer so they open at once and offline. Settings → System → Storage shows what they take up. Remove… clears them all; Keep downloaded mail (Always, a year, 90 days or 30 days) removes older ones a couple of minutes after Hylki starts and every six hours after. Either way the list of every message stays, so the message list and search are unchanged, and a removed message is fetched again when it is opened. Nothing on the server changes.
Keep mail cached, in an account's Syncing settings, downloads every
message of a period ahead of being opened: the last week, month or year, or all
mail. It works on IMAP, JMAP, Microsoft 365 and POP3 accounts, including ones
from GNOME Online Accounts. The default, Newest messages, is the fetch ahead
described above. Trash, Junk and Drafts are left out, and so is OpenPGP mail,
which is only decrypted when opened. Include attachments keeps their files
too; a POP3 account always downloads a message whole, so it has no such
switch, and with a period chosen it downloads older mail than the newest 200
its sync lists, back to the period's start. The download runs
in the background once the account's index is complete, newest first, gives way
whenever a message is opened, and waits on a metered connection when Settings
asks to save data there. A server that refuses it, as Gmail does past its daily
limit, is asked again later, after an hour at most. Keep downloaded mail
does not remove mail inside an account's period, and Remove… clears it,
after which it is downloaded again. Stored as offline_mail and
offline_attachments in accounts.toml.
Hylki follows the desktop's network status (GNetworkMonitor, through the
network portal in the Flatpak). While there is no network it makes no
connections: the timed mail check, the push channels and Send Later wait, the
Refresh button turns orange, and its tooltip says why. The status bar does not
open by itself, but opened it explains the same. A message sent meanwhile
goes to the Outbox, and what waits there is sent for every kind of account
once the network is back. A server on the computer itself, such as Proton
Mail Bridge on 127.0.0.1, is still reached. A desktop can report no
network when there is one (a network without a default route); clicking
Refresh then tries the servers anyway for a minute.
Settings → General → Save data on metered connections, on by default,
holds back the work done ahead of you while the connection is metered:
downloading the newest messages and attachments, indexing older mail for
search, watching folders other than the Inbox, and fetching sender logos and
Gravatar pictures. New mail still arrives, and whatever you open is
fetched. It all resumes once the connection is no longer metered. Stored as
metered_save_data in privacy.toml.
A new-mail notification opens the message when clicked. When it is about a
single message it also carries up to three buttons. Mark as Read,
Archive, Delete (to Trash, with the usual undo in the window) and
Mark as Spam act on the message without raising the window; Reply
and Forward open the message with the composer started. Settings →
General → Notification Buttons picks any three of the six (Mark as Read,
Archive and Delete to begin with); a notification that sums up several new
messages carries none. Stored as notification_buttons in privacy.toml.
Settings → General → Sound for new mail plays a sound with each new-mail
notification. It is off until switched on. Sound picks one of GNOME's four
alert sounds (Click, Hum, String and Swing, built into Hylki) or Custom
File, which adds a Choose… button for a file of your own (any format
GStreamer can play, such as WAV, MP3, OGG or FLAC). Picking a sound plays it,
and so does the play button. A custom file is copied to
~/.local/share/hylki/notification-sound/, so the original can be moved or
deleted; the choice is stored in sound.toml. The desktop's own sound theme
is not offered: the Flatpak cannot read the host's sounds. Several accounts
receiving mail at once play the sound once. Like the notification, the sound
comes only while the window is in the background or closed: GNOME shows no
notification for the app in front. Also play while Hylki is in front
plays it then as well, without a notification. GNOME's own Alert Sound
setting has no say over it, None included. In a native install it is not
played while Do Not Disturb is on; the Flatpak cannot see Do Not Disturb, which the
desktop does not share with sandboxed apps. The desktop may play a sound of
its own for the notification as well; GNOME Settings → Notifications → Hylki →
Sound Alerts turns that one off.
Errors, and the console when Settings → System → Console mode is on, open
in a bar at the bottom of the window. Settings → System → Status bar puts
it at the top instead. Ctrl+Shift+S, or a long press on Refresh,
shows or hides it. Its buttons are, from the left, Export log (while the
console is open), the console, and the bar's own toggle. Stored as
status_bar_top in privacy.toml.
Hylki collects no telemetry and sends no analytics. Remote content in messages is blocked by default to defeat tracking pixels. Passwords and OAuth refresh tokens live in the system keyring (secret-service), never in plain files.
Where things live. Settings are TOML files in ~/.config/hylki/
(accounts.toml, privacy.toml, filters.toml, tags.toml and friends), the
mail index and cached messages in ~/.local/share/hylki/cache.db, the web
views' caches in ~/.cache/hylki/, and account pictures in
~/.local/share/avatars/. A Flatpak install keeps the same layout under
~/.var/app/co.hyprlab.Hylki/. Nothing else on the computer is written to, and
./uninstall.sh --purge (or removing those directories) takes it all away.
Passwords and tokens are never in those files: they go to the system keyring through the Secret Service. Decrypted OpenPGP messages are never cached at all.
Settings → Privacy → Encrypt stored mail encrypts the mail cache. It is
off by default. cache.db holds the message list, every message and
attachment that was opened or kept offline, the Outbox and the addresses
collected from mail, mail that a local bridge decrypted from end-to-end
encryption included. With the switch on, it is a SQLCipher 4 database
(AES-256, with an HMAC on every page) under a random 256-bit key, made the
first time and kept in the keyring as cache-key beside the passwords. A copy
of the file, or a backup of it, is unreadable without that keyring. Reads from
an encrypted cache are a little slower.
The switch takes effect at the next start. The cache is then encrypted in place: an encrypted copy is made and checked against the original table by table, and only then takes its place, so a failure leaves the original as it was. A window shows how far it has got; it takes about a minute for every 2 GB, and quitting from it leaves the cache as it was. The unencrypted file is then deleted, but as with any deleted file, the disk may keep its old blocks until they are written over. Turning the switch off decrypts the cache the same way at the next start.
Versions before 1.48.0-beta.3 cannot open an encrypted cache, and fail to
load mail. Before going back to one, turn Encrypt stored mail off and
restart Hylki once, which decrypts the cache. Otherwise delete
~/.local/share/hylki/cache.db (in the Flatpak,
~/.var/app/co.hyprlab.Hylki/data/hylki/cache.db), and the mail is downloaded
again.
An encrypted cache is never opened unencrypted instead. A window says so when
the keyring is slow to answer. When it is locked, or has not answered within a
minute and a half, holds no key, or holds one that does not open the cache,
Hylki asks before its window opens: Try Again, Quit, or Reset
Cache…, which deletes the cache and downloads the mail again. Mail that
exists only on this computer is then lost: a POP3 account's mail, and unsent
mail in the Outbox. When the keyring cannot be reached at all, Store
Unencrypted… takes the place of the reset: it turns the switch off and
deletes the encrypted cache it cannot open. The switch is stored as the
one-line file cache-encryption in ~/.config/hylki/. The demo (HYLKI_DEMO)
never opens the cache and asks nothing.
Settings → Backup → Export settings writes a file only you can read. It carries no passwords or tokens, and no OAuth client secret either: importing it on the same computer keeps the secret already there, and on another one, an account with its own OAuth client needs the secret typed in again.
Remote content, once allowed for a message, is fetched by Hylki itself, with
no cookies and no Referer, and kept in ~/.cache/hylki/remote/ for a week, up
to 2 GB, so a message shown again does not fetch it again. Settings →
Privacy → Pre-load remote content for the next messages fetches it for the next
three rows in the list, and the one before, while a message is read: only
for mail whose remote content would load anyway, and not on a metered
connection when Settings asks to save data there. It is off by default,
because a sender's tracking pixel then reports a message as opened before you
open it. Stored as remote_ahead in privacy.toml.
Links in messages lose their tracking tags (utm_source and the other
utm_ tags, fbclid, gclid, mc_eid and similar) before the browser opens
them, and Copy Link Address copies them without. A link wrapped by a
redirector that logs the click, such as Google's /url or Facebook's
l.php, opens at the address it carries, when that address is written in the
link itself; nothing is looked up to find it. Outlook Safe Links stay as they
are, because Microsoft Defender checks the address when the link is clicked.
Settings → Privacy → Remove trackers from links turns this off. Stored as
clean_links in privacy.toml.
The reader and the composer never look up the addresses of a message's links ahead of a click (DNS prefetching), which would tell the sender's DNS server that the message was opened.
Attachments that are programs or scripts, such as .desktop, .sh,
.AppImage, .jar or .exe files, or a file whose first bytes say it is
one whatever its name, are asked about before they open: opening one can run
it.
Read receipts are sent only when you press Send Receipt, unless Settings → Privacy → Send read receipts is Always. See Read receipts.
Grammar checking is off until switched on in Settings → Composing. Harper and LanguageTool, once downloaded there, check on this computer and send nothing. With a LanguageTool server chosen instead, what you write in the composer goes to that server as you type, without the quote or the signature. See Grammar checking.
Translation is off until a service is chosen in Settings → Translation. After that, a message's text goes to that service only when you press Translate on it, and encrypted messages never do. See Translating messages.