Woahai321 · renoviana · Jul 7, 2026
diff --git a/api_server.py b/api_server.py
@@ -52,7 +52,8 @@
     get_current_timezone_info,
     get_timezone_from_env,
     normalize_timezone_input,
-    list_supported_abbreviations
+    list_supported_abbreviations,
+    get_all_timezones,
 )
 
 # Global variable to track server start time
@@ -5419,14 +5420,23 @@ async def sync_collection(franchise_name: str):
 
 @app.get("/api/timezone/supported")
 async def get_supported_timezones():
-    """Get list of all supported timezone abbreviations organized by region"""
+    """Get all IANA timezones plus supported abbreviations organized by region"""
     try:
+        timezones = get_all_timezones()
         abbreviations = list_supported_abbreviations()
+        total_abbreviations = sum(
+            len(abbrevs) for abbrevs in abbreviations.values()
+        )
         return {
             "success": True,
+            "timezones": timezones,
+            "total_timezones": len(timezones),
             "regions": abbreviations,
-            "total_abbreviations": sum(len(abbrevs) for abbrevs in abbreviations.values()),
-            "note": "Use these abbreviations in the TZ environment variable"
+            "total_abbreviations": total_abbreviations,
+            "note": (
+                "Use IANA names (preferred) or these abbreviations "
+                "in the TZ environment variable"
+            ),
         }
     except Exception as e:
         raise HTTPException(status_code=500, detail=str(e))

diff --git a/docs/api.md b/docs/api.md
@@ -540,7 +540,26 @@ Returns Overseerr configuration details.
 GET /api/timezone/supported
 ```
 
-Returns list of supported timezones.
+Returns all IANA timezones available on the server (sorted by UTC offset), plus supported abbreviations organized by region.
+
+**Response**:
+```json
+{
+  "success": true,
+  "timezones": [
+    {
+      "value": "America/Sao_Paulo",
+      "label": "America/Sao_Paulo (-03)",
+      "offset": "UTC-03:00"
+    }
+  ],
+  "total_timezones": 598,
+  "regions": {
+    "North America": ["EST", "PST"]
+  },
+  "total_abbreviations": 100
+}
+```
 
 ### Get Current Timezone
 ```http

diff --git a/docs/configuration.md b/docs/configuration.md
@@ -290,9 +290,11 @@ TZ=GMT
 3. Copy the webhook URL to `DISCORD_WEBHOOK_URL`
 
 **Timezone Configuration:**
-- Use standard timezone identifiers (e.g., `GMT+1`, `UTC-5`)
+- Use IANA timezone names (e.g., `America/Sao_Paulo`, `Europe/London`), common abbreviations (e.g., `BRT`, `EST`, `CET`) or UTC/GMT offsets (e.g., `GMT+1`, `UTC-5`)
+- All IANA timezones are supported and can also be selected in the dashboard (Settings → Sync Settings) and in the setup wizard
+- Set `TIMEZONE_REGION` (e.g., `US`, `EU`, `BR`, `ASIA`, `AU`, `NZ`) to resolve ambiguous abbreviations like `AMT` or `IST`
 - Affects scheduling and log timestamps
-- Default: `GMT`
+- Default: `UTC`
 
 ### Performance Tuning
 

diff --git a/list_sync/utils/timezone_utils.py b/list_sync/utils/timezone_utils.py
@@ -4,8 +4,8 @@
 
 import os
 import logging
-from typing import Optional, Dict
-from datetime import datetime, timezone
+from typing import List, Optional, Dict
+from datetime import datetime, timedelta, timezone
 import zoneinfo
 
 # Comprehensive mapping of common timezone abbreviations to their full timezone names
@@ -183,6 +183,9 @@
     "BRT": "America/Sao_Paulo",  # Brasília Time
     "BRST": "America/Sao_Paulo", # Brasília Summer Time
     "BST": "America/Sao_Paulo",  # Brazil Summer Time (conflicts with British Summer Time)
+    "AMT": "America/Manaus",     # Amazon Time (conflicts with Armenia Time)
+    "ACT": "America/Rio_Branco",  # Acre Time (conflicts with ASEAN Common Time)
+    "FNT": "America/Noronha",    # Fernando de Noronha Time
 
     # South America - Argentina
     "ART": "America/Argentina/Buenos_Aires",
@@ -285,6 +288,27 @@
     "Z": "UTC",               # Zulu Time Zone (UTC+0)
 }
 
+# South American zones (used to categorize abbreviations by region,
+# since they share the "America/" prefix with North American zones)
+SOUTH_AMERICAN_TIMEZONES = {
+    "America/Argentina/Buenos_Aires",
+    "America/Asuncion",
+    "America/Bogota",
+    "America/Caracas",
+    "America/Cayenne",
+    "America/Guayaquil",
+    "America/Guyana",
+    "America/La_Paz",
+    "America/Lima",
+    "America/Manaus",
+    "America/Montevideo",
+    "America/Noronha",
+    "America/Paramaribo",
+    "America/Rio_Branco",
+    "America/Santiago",
+    "America/Sao_Paulo",
+}
+
 # Regional preference mapping for conflicting abbreviations
 REGIONAL_PREFERENCES: Dict[str, Dict[str, str]] = {
     "US": {
@@ -323,6 +347,13 @@
     "NZ": {
         "NZST": "Pacific/Auckland",
         "NZDT": "Pacific/Auckland",
+    },
+    "BR": {
+        "BRT": "America/Sao_Paulo",
+        "AMT": "America/Manaus",
+        "ACT": "America/Rio_Branco",
+        "FNT": "America/Noronha",
+        "BST": "America/Sao_Paulo",
     }
 }
 
@@ -556,6 +587,54 @@ def get_current_timezone_info() -> Dict[str, str]:
         }
 
 
+def get_all_timezones() -> List[Dict[str, str]]:
+    """
+    Get all IANA timezones available on the system with display metadata.
+
+    Each entry contains the IANA name (``value``), a human-readable label
+    with the current abbreviation (``label``), and the current UTC offset
+    (``offset``). Zones are sorted by UTC offset, then alphabetically.
+
+    Returns:
+        List of dicts with ``value``, ``label`` and ``offset`` keys, e.g.
+        ``{"value": "America/Sao_Paulo", "label": "America/Sao_Paulo (-03)",
+        "offset": "UTC-03:00"}``
+    """
+    now = datetime.now(timezone.utc)
+    entries = []
+
+    for name in zoneinfo.available_timezones():
+        try:
+            local_now = now.astimezone(zoneinfo.ZoneInfo(name))
+        except Exception as e:
+            logging.debug(f"Skipping unloadable timezone '{name}': {e}")
+            continue
+
+        utc_offset = local_now.utcoffset() or timedelta(0)
+        total_minutes = int(utc_offset.total_seconds() // 60)
+        sign = "+" if total_minutes >= 0 else "-"
+        hours, minutes = divmod(abs(total_minutes), 60)
+        offset_str = f"UTC{sign}{hours:02d}:{minutes:02d}"
+
+        abbreviation = local_now.strftime("%Z")
+        label = f"{name} ({abbreviation})" if abbreviation else name
+
+        entries.append(
+            (
+                total_minutes,
+                name,
+                {
+                    "value": name,
+                    "label": label,
+                    "offset": offset_str,
+                },
+            )
+        )
+
+    entries.sort(key=lambda entry: (entry[0], entry[1]))
+    return [entry[2] for entry in entries]
+
+
 def list_supported_abbreviations() -> Dict[str, list]:
     """
     Get a list of all supported timezone abbreviations organized by region.
@@ -577,28 +656,26 @@ def list_supported_abbreviations() -> Dict[str, list]:
 
     # Categorize abbreviations
     for abbrev, tz_name in TIMEZONE_ABBREVIATIONS.items():
-        if tz_name.startswith("America/"):
+        if len(abbrev) == 1:  # Military single-letter codes
+            regions["Military"].append(abbrev)
+        elif abbrev in ["UTC", "GMT"]:
+            regions["Universal"].append(abbrev)
+        elif tz_name in SOUTH_AMERICAN_TIMEZONES:
+            regions["South America"].append(abbrev)
+        elif tz_name.startswith("America/"):
             regions["North America"].append(abbrev)
         elif tz_name.startswith("Europe/"):
             regions["Europe"].append(abbrev)
         elif tz_name.startswith("Asia/"):
             regions["Asia"].append(abbrev)
-        elif tz_name.startswith("Australia/") or tz_name.startswith("Pacific/Auckland"):
+        elif tz_name.startswith("Australia/") or tz_name == "Pacific/Auckland":
             regions["Australia/New Zealand"].append(abbrev)
         elif tz_name.startswith("Africa/"):
             regions["Africa"].append(abbrev)
         elif tz_name.startswith("Pacific/"):
             regions["Pacific"].append(abbrev)
-        elif len(abbrev) == 1:  # Military single-letter codes
-            regions["Military"].append(abbrev)
-        elif abbrev in ["UTC", "GMT", "Z"]:
-            regions["Universal"].append(abbrev)
         else:
-            # Determine by timezone name patterns
-            if any(continent in tz_name for continent in ["America/Argentina", "America/Sao_Paulo", "America/Santiago"]):
-                regions["South America"].append(abbrev)
-            else:
-                regions["Universal"].append(abbrev)
+            regions["Universal"].append(abbrev)
 
     # Sort each region's abbreviations
     for region in regions:

diff --git a/listsync-nuxt/components/settings/SyncSettings.vue b/listsync-nuxt/components/settings/SyncSettings.vue
@@ -177,27 +177,29 @@ const showTimezoneDropdown = ref(false)
 const supportedTimezones = ref<any[]>([])
 const currentTimezoneInfo = ref<any>(null)
 
-// Fallback timezones if API fails
-const fallbackTimezones = [
-  { label: 'UTC', value: 'UTC', offset: '+00:00' },
-  { label: 'America/New_York (EST/EDT)', value: 'America/New_York', offset: 'UTC-05:00' },
-  { label: 'America/Chicago (CST/CDT)', value: 'America/Chicago', offset: 'UTC-06:00' },
-  { label: 'America/Denver (MST/MDT)', value: 'America/Denver', offset: 'UTC-07:00' },
-  { label: 'America/Los_Angeles (PST/PDT)', value: 'America/Los_Angeles', offset: 'UTC-08:00' },
-  { label: 'Europe/London (GMT/BST)', value: 'Europe/London', offset: 'UTC+00:00' },
-  { label: 'Europe/Paris (CET/CEST)', value: 'Europe/Paris', offset: 'UTC+01:00' },
-  { label: 'Asia/Tokyo (JST)', value: 'Asia/Tokyo', offset: 'UTC+09:00' },
-  { label: 'Australia/Sydney (AEDT)', value: 'Australia/Sydney', offset: 'UTC+11:00' },
-]
+// Fallback: IANA timezones provided by the browser if the API fails
+const getBrowserTimezones = () => {
+  try {
+    return Intl.supportedValuesOf('timeZone').map((tz) => ({
+      label: tz,
+      value: tz,
+      offset: '',
+    }))
+  } catch {
+    return [{ label: 'UTC', value: 'UTC', offset: 'UTC+00:00' }]
+  }
+}
 
 // Load supported timezones
 const loadTimezones = async () => {
   try {
     const response: any = await api.getSupportedTimezones()
-    supportedTimezones.value = response.timezones || fallbackTimezones
+    supportedTimezones.value = response.timezones?.length
+      ? response.timezones
+      : getBrowserTimezones()
   } catch (error) {
-    console.error('Error loading timezones, using fallback:', error)
-    supportedTimezones.value = fallbackTimezones
+    console.error('Error loading timezones, using browser fallback:', error)
+    supportedTimezones.value = getBrowserTimezones()
   }
 }
 
@@ -247,19 +249,6 @@ onMounted(() => {
   timezoneSearch.value = localValue.value.timezone || ''
 })
 
-// Timezone options (common timezones)
-const timezoneOptions = [
-  { label: 'UTC', value: 'UTC' },
-  { label: 'America/New_York (EST/EDT)', value: 'America/New_York' },
-  { label: 'America/Chicago (CST/CDT)', value: 'America/Chicago' },
-  { label: 'America/Denver (MST/MDT)', value: 'America/Denver' },
-  { label: 'America/Los_Angeles (PST/PDT)', value: 'America/Los_Angeles' },
-  { label: 'Europe/London (GMT/BST)', value: 'Europe/London' },
-  { label: 'Europe/Paris (CET/CEST)', value: 'Europe/Paris' },
-  { label: 'Asia/Tokyo (JST)', value: 'Asia/Tokyo' },
-  { label: 'Australia/Sydney (AEDT/AEST)', value: 'Australia/Sydney' },
-]
-
 // Watch for external changes
 watch(
   () => props.modelValue,

diff --git a/listsync-nuxt/components/setup/Step2Configuration.vue b/listsync-nuxt/components/setup/Step2Configuration.vue
@@ -95,8 +95,8 @@
             class="w-full px-3 py-2.5 sm:py-2 h-11 sm:h-10 bg-black/30 border border-purple-500/25 rounded-lg text-base sm:text-sm text-foreground focus:outline-none focus:ring-2 focus:ring-purple-500/50 transition-all touch-manipulation"
             :disabled="isValidating"
           >
-            <option v-for="tz in commonTimezones" :key="tz" :value="tz">
-              {{ tz }}
+            <option v-for="tz in timezoneOptions" :key="tz.value" :value="tz.value">
+              {{ tz.label }}
             </option>
           </select>
         </div>
@@ -274,27 +274,34 @@ watch(() => localValue.value.trakt_client_id, () => {
   traktValidated.value = false
 })
 
-// Common timezones for quick selection
-const commonTimezones = [
-  'UTC',
-  'America/New_York',
-  'America/Chicago',
-  'America/Denver',
-  'America/Los_Angeles',
-  'America/Toronto',
-  'America/Vancouver',
-  'Europe/London',
-  'Europe/Paris',
-  'Europe/Berlin',
-  'Europe/Amsterdam',
-  'Asia/Tokyo',
-  'Asia/Shanghai',
-  'Asia/Hong_Kong',
-  'Asia/Singapore',
-  'Australia/Sydney',
-  'Australia/Melbourne',
-  'Pacific/Auckland',
-]
+// Fallback: IANA timezones provided by the browser if the API fails
+const getBrowserTimezones = () => {
+  try {
+    return Intl.supportedValuesOf('timeZone').map((tz) => ({
+      value: tz,
+      label: tz,
+    }))
+  } catch {
+    return [{ value: 'UTC', label: 'UTC' }]
+  }
+}
+
+// All IANA timezones, loaded from the API
+const timezoneOptions = ref(getBrowserTimezones())
+
+onMounted(async () => {
+  try {
+    const response: any = await api.getSupportedTimezones()
+    if (response?.timezones?.length) {
+      timezoneOptions.value = response.timezones.map((tz: any) => ({
+        value: tz.value,
+        label: `${tz.value} (${tz.offset})`,
+      }))
+    }
+  } catch (error) {
+    console.error('Error loading timezones, using browser fallback:', error)
+  }
+})
 
 // Check if we can proceed (basic validation)
 const canProceed = computed(() => {