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MetaMask SDK documentation

Seamlessly connect to the MetaMask extension and mobile app.

Connect to MetaMask using JavaScript

Get started with MetaMask SDK in your JavaScript dapp. You can set up the SDK in the following ways:

JavaScript SDK Quickstart

Prerequisites​

  • Node.js version 19 or later installed.
  • A package manager installed, such as npm, Yarn, pnpm, or bun.
  • MetaMask installed in your browser or on mobile.

Set up using a template​

  1. Download the MetaMask SDK JavaScript template:

    npx degit MetaMask/metamask-sdk-examples/quickstarts/javascript metamask-javascript

    degit is a tool that enables cloning only the directory structure from a GitHub repository, without retrieving the entire repository.

  2. Navigate into the repository:

    cd metamask-javascript
    GitHub clone instead of degit?

    Clone the MetaMask SDK examples repository and navigate into the quickstarts/javascript directory:

    git clone https://github.com/MetaMask/metamask-sdk-examples
    cd metamask-sdk-examples/quickstarts/javascript

    Note: this will download the entire repository.

  3. Install dependencies:

    pnpm install

  4. Run the project:

    pnpm dev

You've successfully set up MetaMask SDK.

Set up manually​

1. Install the SDK​

Install the SDK in an existing JavaScript project:

npm install @metamask/sdk

2. Initialize the SDK​

The following are examples of using the SDK in various JavaScript environments:

import { MetaMaskSDK } from '@metamask/sdk'

const MMSDK = new MetaMaskSDK({
  dappMetadata: {
    name: 'Example JavaScript dapp',
    url: window.location.href,
    // iconUrl: "https://mydapp.com/icon.png" // Optional
  },
  infuraAPIKey: process.env.INFURA_API_KEY,
})

These examples configure the SDK with the following options:

  • dappMetadata - Ensures trust by showing your dapp's name, url, and iconUrl during connection.

  • infuraAPIKey - Enables read-only RPC and load‑balancing.

3. Connect and use provider​

Connect to MetaMask and get the provider for RPC requests:

const provider = MMSDK.getProvider()

const accounts = await MMSDK.connect()
console.log('Connected account:', accounts[0])

const result = await provider.request({
  method: 'eth_accounts',
  params: [],
})
console.log('eth_accounts result:', result)

MMSDK.connect() handles cross-platform connection (desktop and mobile), including deeplinking.

Use provider.request() for arbitrary JSON-RPC requests like eth_chainId or eth_getBalance, or for batching requests via metamask_batch.

Common SDK methods at a glance​

MethodDescription
connect()Triggers wallet connection flow
connectAndSign({ msg: '...' })Connects and prompts user to sign a message
getProvider()Returns the provider object for RPC requests
provider.request({ method, params })Calls any Ethereum JSON‑RPC method
Batched RPCUse metamask_batch to group multiple JSON-RPC requests

Usage example​

// 1. Connect and get accounts
const accounts = await MMSDK.connect()

// 2. Connect and sign in one step
const signResult = await MMSDK.connectAndSign({
  msg: 'Sign in to Dapp',
})

// 3. Get provider for RPC requests
const provider = MMSDK.getProvider()

// 4. Make an RPC request
const result = await provider.request({
  method: 'eth_accounts',
  params: [],
})

// 5. Batch multiple RPC requests
const batchResults = await provider.request({
  method: 'metamask_batch',
  params: [{ method: 'eth_accounts' }, { method: 'eth_chainId' }],
})

Live example​

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