MetaMask Snaps Introduction

Snaps is a system that allows developers to safely build and expand the capabilities of MetaMask. It is a program that is run in an isolated environment with a limited set of capabilities, that can customize and modify MetaMask's wallet experience for end users. For example, a snap can add new APIs to MetaMask thus adding support for different blockchains or modify existing functionalities using internal APIs.

Additional information can be found here.

Usage

1. Enable bob-snap in your dapp

const result: boolean = await ethereum.request({
  method: 'wallet_requestSnaps',
  params: {
    'npm:@gobob/bob-snap': {},
  },
});

2. Get an extended public key

const response = await ethereum.request({
  method: 'wallet_invokeSnap',
  params: {
    snapId: 'npm:@gobob/bob-snap',
    request: {
      method: 'btc_getPublicExtendedKey',
      params: {
        network: 'test',
        scriptType: 'P2WPKH',
      },
    },
  },
});

3. Sign Psbt

const result: {txId: string; txHex: string} = await ethereum.request({
  method: 'wallet_invokeSnap',
  params: {
    snapId: 'npm:@gobob/bob-snap',
    request: {
      method: 'btc_signPsbt',
      params: {
        psbt: base64Psbt, // base64 string for the pbst,
        network: 'Main', // for testnet use "Test",
        scriptType: 'P2PKH', // "P2SH-P2WPKH" or "P2WPKH"
      },
    },
  },
});

Building

Build the snap and test it locally with the following command:

yarn rebuild

Testing

Use the following command to run tests:

yarn test