@babylonlabs-io/wallet-connector

@babylonlabs-io/wallet-connector

Babylon Wallet Connector

• Key Features
• Overview
• Installation
• Version Release
  • Stable version
• Storybook
• Wallet Integration
  • 1. Browser extension wallets
  • 2. Mobile wallets
  • IProvider
    • IBTCProvider
    • IBBNProvider
    • SignPsbtOptions
    • IETHProvider
  • Wallet Injection
• Vault Integration Guide

The Babylon Wallet Connector repository provides the wallet connection component used in Babylon dApps. This component enables the connection of Bitcoin, Babylon Genesis chain, and Ethereum wallets.

Key Features

• Unified interfaces for Bitcoin, Babylon, and Ethereum wallet connections
• Support for browser extension wallets
• Support for hardware wallets
• Mobile wallet compatibility through injectable interfaces
• Tomo Connect integration for broader wallet ecosystem

Overview

The Babylon Wallet Connector provides a unified interface for integrating Bitcoin, Babylon, and Ethereum wallets into Babylon dApps. It supports native wallet extensions, injectable mobile wallets, and AppKit/WalletConnect for ETH.

The main architectural difference is that native wallets are built into the library, while injectable wallets can be dynamically added by injecting their implementation into the webpage's window object before the dApp loads.

Installation

npm i @babylonlabs-io/wallet-connector

Commit Format & Automated Releases

This project uses Conventional Commits and semantic-release to automate versioning, changelog generation, and npm publishing.

How It Works

1. All commits must follow the Conventional Commits format.
2. When changes are merged into the main branch:
   • semantic-release analyzes commit messages
   • Determines the appropriate semantic version bump (major, minor, patch)
   • Tags the release in Git with release change log
   • Publishes the new version to npm

Commit Message Examples

feat: add support for slashing script
fix: handle invalid staking tx gracefully
docs: update README with commit conventions
refactor!: remove deprecated method and cleanup types

Note: For breaking changes, add a ! after the type ( e.g. feat!: or refactor!:) and include a description of the breaking change in the commit body.

Releasing

Just commit your changes using the proper format and merge to main. The CI pipeline will handle versioning and releasing automatically — no manual tagging or version bumps needed.

Storybook

npm run dev

Wallet Integration

IMPORTANT: Breaking changes to the wallet methods used by the Babylon web application are likely to cause incompatibility with it or lead to unexpected behavior with severe consequences.

Please make sure to always maintain backwards compatibility and test thoroughly all changes affecting the methods required by the Babylon web application. If you are unsure about a change, please reach out to the Babylon Labs team.

This guide explains how to integrate wallets with Babylon dApps. The wallet connector supports Bitcoin, Babylon, and Ethereum wallets through two integration paths:

1. Browser extension wallets

The recommended way to integrate your wallet with Babylon dApps is through Tomo Connect SDK Lite. Please refer to Tomo's documentation for integration details.

2. Mobile wallets

Full interface definitions can be found in src/core/types.ts.

Below we outline the interfaces for Bitcoin, Babylon, and Ethereum wallets that need to be implemented for integration with Babylon dApps.

IProvider

export interface IProvider {
  /**
   * Connects to the wallet and returns the instance of the wallet provider.
   * Currently Bitcoin only supports Native SegWit and Taproot address types.
   * @returns A promise that resolves to an instance of the wrapper wallet provider.
   * @throws An error if the wallet is not installed or if connection fails.
   */
  connectWallet(): Promise<void>;

  /**
   * Gets the address of the connected wallet.
   * @returns A promise that resolves to the address of the connected wallet.
   */
  getAddress(): Promise<string>;

  /**
   * Gets the public key of the connected wallet.
   * @returns A promise that resolves to the public key of the connected wallet.
   */
  getPublicKeyHex(): Promise<string>;
}

IBTCProvider

interface IBTCProvider extends IProvider {
  /**
   * Signs the given PSBT in hex format.
   * @param psbtHex - The hex string of the unsigned PSBT to sign.
   * @param options - Optional parameters for signing the PSBT.
   * @returns A promise that resolves to the hex string of the signed PSBT.
   */
  signPsbt(psbtHex: string, options?: SignPsbtOptions): Promise<string>;

  /**
   * Signs multiple PSBTs in hex format.
   * @param psbtsHexes - The hex strings of the unsigned PSBTs to sign.
   * @param options - Optional parameters for signing the PSBTs.
   * @returns A promise that resolves to an array of hex strings, each representing a signed PSBT.
   */
  signPsbts(
    psbtsHexes: string[],
    options?: SignPsbtOptions[],
  ): Promise<string[]>;

  /**
   * Gets the network of the current account.
   * @returns A promise that resolves to the network of the current account.
   */
  getNetwork(): Promise<Network>;

  /**
   * Signs a message using either BIP322-Simple or ECDSA signing method.
   * @param message - The message to sign.
   * @param type - The signing method to use.
   * @returns A promise that resolves to the signed message.
   */
  signMessage(
    message: string,
    type: "bip322-simple" | "ecdsa",
  ): Promise<string>;

  /**
   * Retrieves the inscriptions for the connected wallet.
   * @returns A promise that resolves to an array of inscriptions.
   */
  getInscriptions(): Promise<InscriptionIdentifier[]>;

  /**
   * Registers an event listener for the specified event.
   * At the moment, only the "accountChanged" event is supported.
   * @param eventName - The name of the event to listen for.
   * @param callBack - The callback function to be executed when the event occurs.
   */
  on(eventName: string, callBack: () => void): void;

  /**
   * Unregisters an event listener for the specified event.
   * @param eventName - The name of the event to listen for.
   * @param callBack - The callback function to be executed when the event occurs.
   */
  off(eventName: string, callBack: () => void): void;

  /**
   * Gets the name of the wallet provider.
   * @returns A promise that resolves to the name of the wallet provider.
   */
  getWalletProviderName(): Promise<string>;

  /**
   * Gets the icon of the wallet provider.
   * @returns A promise that resolves to the icon of the wallet provider.
   */
  getWalletProviderIcon(): Promise<string>;

  /**
   * Gets the version of the wallet provider.
   * @returns A promise that resolves to the version of the wallet provider.
   */
  getVersion?(): Promise<string>;
}

IBBNProvider

export interface IBBNProvider extends IProvider {
  /**
   * Gets the name of the wallet provider.
   * @returns A promise that resolves to the name of the wallet provider.
   */
  getWalletProviderName(): Promise<string>;

  /**
   * Gets the icon of the wallet provider.
   * @returns A promise that resolves to the icon of the wallet provider.
   */
  getWalletProviderIcon(): Promise<string>;

  /**
   * Retrieves an offline signer that supports both Amino and Direct signing methods.
   * This signer is used for signing transactions offline before broadcasting them to the network.
   *
   * @returns {Promise<OfflineAminoSigner & OfflineDirectSigner>} A promise that resolves to a signer supporting both Amino and Direct signing
   * @throws {Error} If wallet connection is not established or signer cannot be retrieved
   */
  getOfflineSigner(): Promise<OfflineAminoSigner & OfflineDirectSigner>;

  /**
   * Retrieves an offline signer that supports either Amino or Direct signing methods.
   * This is required for compatibility with older wallets and hardware wallets (like Ledger) that do not support both signing methods.
   * This signer is used for signing transactions offline before broadcasting them to the network.
   *
   * @returns {Promise<OfflineAminoSigner & OfflineDirectSigner>} A promise that resolves to a signer supporting either Amino or Direct signing
   * @throws {Error} If wallet connection is not established or signer cannot be retrieved
   */
  getOfflineSignerAuto?(): Promise<OfflineAminoSigner | OfflineDirectSigner>;

  /**
   * Registers an event listener for the specified event.
   * At the moment, only the "accountChanged" event is supported.
   * @param eventName - The name of the event to listen for.
   * @param callBack - The callback function to be executed when the event occurs.
   */
  on(eventName: string, callBack: () => void): void;

  /**
   * Unregisters an event listener for the specified event.
   * @param eventName - The name of the event to listen for.
   * @param callBack - The callback function to be executed when the event occurs.
   */
  off(eventName: string, callBack: () => void): void;

  /**
   * Gets the version of the wallet provider.
   * @returns A promise that resolves to the version of the wallet provider.
   */
  getVersion?(): Promise<string>;
}

SignPsbtOptions

export interface SignInputOptions {
  /** Input index to sign */
  index: number;
  /** Address for signing (optional) */
  address?: string;
  /** Public key for signing (optional, hex string) */
  publicKey?: string;
  /** Sighash types (optional) */
  sighashTypes?: number[];
  /**
   * Whether the wallet should sign with the tweaked (key-path) signer.
   * Set `false` for Taproot script-path spends, where signing uses
   * the untweaked internal key. If omitted, the wallet applies its
   * default behavior.
   */
  useTweakedSigner?: boolean;
}

export interface SignPsbtOptions {
  /** Whether to automatically finalize the PSBT after signing */
  autoFinalized?: boolean;
  /**
   * Specific inputs to sign.
   * If not provided, wallet will attempt to sign all inputs it
   * can.
   */
  signInputs?: SignInputOptions[];
}

IETHProvider

export interface IETHProvider extends IProvider {
  /**
   * Signs a message using personal_sign (EIP-191).
   */
  signMessage(message: string): Promise<string>;

  /**
   * Signs structured data using eth_signTypedData_v4 (EIP-712).
   */
  signTypedData(typedData: ETHTypedData): Promise<string>;

  /**
   * Sends a transaction to the blockchain.
   * @returns Transaction hash
   */
  sendTransaction(
    tx: ETHTransactionRequest,
  ): Promise<string>;

  /**
   * Estimates gas for a transaction.
   */
  estimateGas(
    tx: ETHTransactionRequest,
  ): Promise<bigint>;

  /**
   * Gets the current chain ID.
   */
  getChainId(): Promise<number>;

  /**
   * Switches to a different chain.
   */
  switchChain(chainId: number): Promise<void>;

  /**
   * Gets the account balance in wei.
   */
  getBalance(): Promise<bigint>;

  /**
   * Gets the account nonce.
   */
  getNonce(): Promise<number>;

  /**
   * Gets network information.
   */
  getNetworkInfo(): Promise<NetworkInfo>;

  /**
   * Gets the wallet provider name (synchronous).
   */
  getWalletProviderName(): string;

  /**
   * Gets the wallet provider icon (synchronous).
   */
  getWalletProviderIcon(): string;

  on(eventName: string, handler: Function): void;
  off(eventName: string, handler: Function): void;
}

export interface ETHTransactionRequest {
  to: string;
  value?: string;
  data?: string;
  gasLimit?: bigint;
  maxFeePerGas?: bigint;
  maxPriorityFeePerGas?: bigint;
  nonce?: number;
}

export interface ETHTypedData {
  domain: {
    name?: string;
    version?: string;
    chainId?: number;
    verifyingContract?: string;
    salt?: string;
  };
  types: Record<
    string,
    Array<{ name: string; type: string }>
  >;
  primaryType: string;
  message: Record<string, any>;
}

export interface NetworkInfo {
  name: string;
  chainId: string;
}

Note: getWalletProviderName() and getWalletProviderIcon() on IETHProvider are synchronous (return string), unlike the async versions on IBTCProvider and IBBNProvider.

ETH wallets connect via AppKit / WalletConnect (standard EIP-1193). No window.ethwallet injection is supported.

Wallet Injection

1. Implement provider interface
2. Inject into window before loading dApp:

// For Bitcoin wallets
window.btcwallet = new BTCWalletImplementation();

// For Babylon wallets
window.bbnwallet = new BBNWalletImplementation();

// For Ethereum wallets — no injection needed.
// ETH connects via AppKit / WalletConnect.

Vault Integration Guide

For detailed documentation on integrating wallets with Babylon's Trustless Bitcoin Vaults (TBV), including the full deposit transaction flow, signing options, and reference implementations, see the Vault Integration Guide.