RGB Lib Bare bindings

Bare-runtime native addon for the rgb-lib Rust library — built to plug RGB into the Tether WDK (Wallet Development Kit) alongside BTC, EVM, TON, Solana, and the other chains WDK supports.

This project includes rgb-lib as a git submodule, wraps its C FFI via binding.cc, and builds a .bare native addon using cmake-bare. The static library is statically linked into the addon so a single .bare file is self-contained — required for iOS and optimal for Android.

Why Bare?

Node.js bindings (rgb-lib-nodejs) and Swift bindings (rgb-lib-swift) cover desktop and native iOS. This package exists for a specific consumer: the Tether WDK (Wallet Development Kit). WDK runs its chain-specific wallet logic inside a Bare worklet — a sandboxed JS runtime that executes inside the host app via react-native-bare-kit on mobile or as a subprocess on desktop. Each supported chain (BTC, EVM, TON, Solana, etc.) ships as a @wdk/wallet-* package that runs inside the worklet.

For RGB to join WDK, rgb-lib needs to be callable from inside that worklet. That means:

• The native code must link statically into a .bare addon (worklets can't dlopen shared libraries the way Node can — and iOS App Store policy forbids dynamic linking anyway).
• The JS API must be the same shape as @utexo/rgb-lib (the Node.js package) so @utexo/wdk-wallet-rgb and rgb-sdk can write one code path that works in both runtimes via the @utexo/rgb-lib universal loader.

This package is the layer that makes both possible. Consumers don't import it directly in React Native code — they import @utexo/rgb-lib (or use WDK), and the universal loader picks rgb-lib-bare when it detects the bare runtime.

Platform support

Bindings are pre-built and distributed as a single package containing static libraries (.a) for all supported targets. The cmake-bare build system picks the correct one at install time.

Platform	Target	Linking
iOS arm64	aarch64-apple-ios	Static
iOS arm64 sim	aarch64-apple-ios-sim	Static
iOS x64 sim	x86_64-apple-ios	Static
macOS arm64	aarch64-apple-darwin	Static
Android arm64	aarch64-linux-android	Static
Android arm	armv7-linux-androideabi	Static
Android x64	x86_64-linux-android	Static
Android x86	i686-linux-android	Static

Static linking is required for iOS (App Store policy) and gives a single self-contained .bare addon on Android.

Requirements

• Node.js 18+ (for cmake-bare and install scripts)
• bare runtime (for actually running the addon)

Installation

You don't normally install this package directly. It's a transitive dependency of @utexo/wdk-wallet-rgb, which gets pulled in automatically when you use WDK with the RGB chain enabled.

If you are building something that runs inside a bare worklet and need rgb-lib directly, you can install it explicitly:

npm install @utexo/rgb-lib-bare

A postinstall script fetches the pre-built static libraries and .bare prebuilds from this repo's GitHub Releases. No Rust toolchain or cross-compiler is needed on the consumer machine.

Usage

const rgblib = require('@utexo/rgb-lib-bare')

// Generate keys for a new wallet
const keys = rgblib.generateKeys(rgblib.BitcoinNetwork.Regtest)
console.log(keys)

// Create a wallet, use it, then drop it to free native memory
const wallet = new rgblib.Wallet(walletData)
try {
  const address = wallet.getAddress()
  const balance = wallet.getBtcBalance(online, /*skipSync*/ false)
  // ... more operations
} finally {
  wallet.drop()
}

The JavaScript API is class-based and mirrors the shape of @utexo/rgb-lib (the Node.js package) so code can be written once and run in either runtime through the @utexo/rgb-lib universal loader.

⚠️ Memory must be freed manually.

Wallet, Online, Invoice, and VssBackupClient instances hold native resources. Always call .drop() when you're done, or wrap usage in a try…finally block. Failing to drop will leak Rust-owned memory.

C FFI coverage

All 50 functions from rgb-lib's C FFI (v0.3.0-beta.15) are wrapped:

• Wallet lifecycle — newWallet, generateKeys, restoreKeys, goOnline
• Queries — getAddress, getBtcBalance, getAssetBalance, getAssetMetadata, getFeeEstimation, listAssets, listTransfers, listTransactions, listUnspents
• UTXO management — createUtxos, createUtxosBegin, createUtxosEnd
• Send / receive — send, sendBegin, sendEnd, sendBtc, sendBtcBegin, sendBtcEnd, blindReceive, witnessReceive
• Asset issuance — issueAssetNia, issueAssetCfa, issueAssetIfa, issueAssetUda, inflate
• PSBT — signPsbt, finalizePsbt
• Invoice — invoiceNew, invoiceData, invoiceString
• Transfer ops — refresh, sync, deleteTransfers, failTransfers
• Backup — backup, backupInfo, restoreBackup, validateConsignment
• VSS backup — newVssBackupClient, configureVssBackup, vssBackup, vssBackupInfo, vssBackupClientEncryptionEnabled, vssDeleteBackup, disableVssAutoBackup, restoreFromVss

Build and publish

If you are a maintainer and want to build and release this project from source:

# Update the submodule to the desired rgb-lib tag
git submodule update --init --recursive
cd rgb-lib && git checkout v0.3.0-beta.15 && cd ..

# Install Node dependencies (cmake-bare, cmake-npm)
npm install

# Cross-compile the Rust static library for all targets
bash scripts/build-ios.sh all

# Build the .bare prebuilds via cmake-bare for each target
bash scripts/build-prebuilds.sh

# Upload assets to a GitHub Release
gh release create v0.3.0-beta.15 \
  lib/*/librgblibcffi.a prebuilds/*/utexo__rgb-lib-bare.bare

# Publish to npm (maintainers only)
npm publish

CI/CD is configured in .github/workflows/release.yml: every tag of rgb-lib fires a repository_dispatch that builds all 8 targets, uploads assets, and publishes to npm automatically.

Architecture

rgb-lib (Rust)                  ← source of truth, as a submodule
  └── bindings/c-ffi/           ← cbindgen → rgblib.h
        └── cargo rustc          → librgblibcffi.a (static, per target)
              ↑
rgb-lib-bare (this repo)         ← cmake-bare + binding.cc
  └── binding.cc                 ← wraps the C FFI with bare's <js.h> API
  └── CMakeLists.txt             ← links librgblibcffi.a statically
        ↓
      utexo__rgb-lib-bare.bare   ← the loadable bare addon

The key difference from rgb-lib-nodejs: node-gyp links dynamically at runtime, while cmake-bare links statically at build time. Everything else (the underlying rgb-lib Rust crate and the C FFI layer) is identical.