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Use MetaMask SDK with React Native

You can import MetaMask SDK into your React Native dapp to enable your users to easily connect with their MetaMask Mobile wallet.

How it works​

When a user accesses your mobile React Native dapp, the SDK automatically deeplinks to MetaMask Mobile (or if the user doesn't already have it, prompts them to install it). Once the user accepts the connection, they're automatically redirected back to your dapp. This happens for all actions that need user approval.

SDK React Native example

You can download the React Native example. Install the example using yarn setup and run it using yarn ios or yarn android.

Prerequisites​

Install the SDK​

Coming soon

A metamask-react-native-sdk package that simplifies the installation of the SDK for React Native dapps is coming soon.

Use rn-nodeify to install the SDK. In your project directory, install rn-nodeify:

yarn add --dev rn-nodeify
or
npm i --dev rn-nodeify

Install the rn-nodeify libraries:

yarn add react-native-crypto
yarn add react-native-randombytes
yarn add crypto
yarn add process
yarn add stream
yarn add events

In your project's package.json file, insert the rn-nodeify command into the postinstall script:

package.json
"scripts": {
  ...,
  "postinstall": "rn-nodeify --install 'crypto,process,stream,events' --hack"
}

rn-nodeify creates a shim.js file in your project root directory. Import it in the root file of your application:

import './shim'

Install react-native-background-timer:

yarn add react-native-background-timer

cd ios && pod install && cd ..

Install MetaMask SDK:

yarn add @metamask/sdk

Run the postinstall script after everything is installed:

yarn postinstall

Finally, install the necessary pods that come with the libraries:

cd ios && pod install && cd ..

Use the SDK​

Import, instantiate, and use the SDK by adding something similar to the following to your project script:

import MetaMaskSDK from '@metamask/sdk';
import { Linking } from 'react-native';
import BackgroundTimer from 'react-native-background-timer';

const MMSDK = new MetaMaskSDK({
  openDeeplink: (link) => {
    Linking.openURL(link); // Use React Native Linking method or your favourite way of opening deeplinks
  },
  timer: BackgroundTimer, // To keep the app alive once it goes to background
  dappMetadata: {
    name: 'My App', // The name of your application
    url: 'https://myapp.com', // The url of your website
  },
});

const ethereum = MMSDK.getProvider();

const accounts = await ethereum.request({ method: 'eth_requestAccounts' });

You can configure the SDK using any options and call any provider API methods. Always call eth_requestAccounts using ethereum.request() first, since it prompts the installation or connection popup to appear.

You can use EthersJS with your React Native app:

const provider = new ethers.providers.Web3Provider(ethereum);

// Get the balance of an account (by address or ENS name, if supported by network)
const balance = await provider.getBalance(ethereum.selectedAddress);

// Often you need to format the output to something more user-friendly,
// such as in ether (instead of wei)
const balanceInETH = ethers.utils.formatEther(balance);
// '0.182826475815887608'