Create a React Native App

Prerequisites

Deeplink handling

Your app needs to be correctly configured to handle Universal Links (iOS) and App Links (Android). At runtime, a link like https://your-app.example.com/mobile-wallet-protocol should be able to open up your app for smart wallet to send responses back.

Follow this Expo Guide for detailed instructions on setting up deeplinks in the Expo environment, this is a required setup for smart wallet to work.

Install peer dependencies

The Mobile Wallet Protocol Client library requires the Expo WebBrowser and Async Storage packages to be installed. Follow the instructions on the respective pages for any additional setup.

npm

npm i expo expo-web-browser @react-native-async-storage/async-storage

Polyfills

Mobile Wallet Protocol Client requires crypto.randomUUID, crypto.getRandomValues, and URL to be polyfilled globally since they are not available in the React Native environment.

Below is an example of how to polyfill these functions in your app using the expo-crypto and expo-standard-web-crypto packages.

npm

npm i expo-crypto expo-standard-web-crypto react-native-url-polyfill

polyfills.js

import "react-native-url-polyfill/auto";
import { polyfillWebCrypto } from "expo-standard-web-crypto";
import { randomUUID } from "expo-crypto";
 
polyfillWebCrypto();
crypto.randomUUID = randomUUID;

Setup

Install Mobile Wallet Protocol Client

Add the latest version of Mobile Wallet Protocol Client to your project.

npm

npm i @mobile-wallet-protocol/client@latest

Configuration

Next, set up your app to pass in deeplinks coming from Smart Wallet to Mobile Wallet Protocol Client so that it can handle responses to the requests you make. In your app, this might look something like the following.

Below is an example of how to set up deeplink handling in your app using the Expo Linking module.

App.tsx

import { handleResponse } from "@mobile-wallet-protocol/client";
import * as Linking from "expo-linking";
 
// ...
 
useEffect(() => {
  const subscription = Linking.addEventListener("url", ({ url }) => {
    const handled = handleResponse(url);
    if (!handled) {
      // handle other deeplinks
    }
  });
 
  return () => subscription.remove();
}, []);

Usage

Mobile Wallet Protocol Client provides 2 interfaces for mobile app to interact with the Smart Wallet, an EIP-1193 compliant provider interface and a wagmi connector.

Option 1: EIP-1193 Provider

Create a new EIP1193Provider instance, which is EIP-1193 compliant.

The appDeeplinkUrl is required and should match the deeplink URL you set up earlier.

App.tsx

import { EIP1193Provider } from "@mobile-wallet-protocol/client";
 
// Step 1. Initialize provider with your dapp's metadata and target wallet
const metadata = {
  appDeeplinkUrl: "https://your-app.example.com", // required to establish your app's identity, use 'https://' link for production
  appCustomScheme: "myapp://", // optional, used to remove the Done screen after signing
  appName: "My App Name",
  appChainIds: [8453],
  appLogoUrl: "https://example.com/logo.png",
};
const provider = new EIP1193Provider({
  metadata,
  wallet: Wallets.CoinbaseSmartWallet,
});
 
// ...
 
// 2. Use the provider
const addresses = await provider.request({ method: "eth_requestAccounts" });
const signedData = await provider.request({
  method: "personal_sign",
  params: ["0x48656c6c6f20776f726c6421", addresses[0]],
});

Option 2: Wagmi Connector

Add the latest verion of Mobile Wallet Protocol wagmi-connectors to your project.

npm

npm i @mobile-wallet-protocol/wagmi-connectors@latest

Simply import the createConnectorFromWallet function and pass in the wallet you want to use to wagmi config.

config.ts

import {
  createConnectorFromWallet,
  Wallets,
} from "@mobile-wallet-protocol/wagmi-connectors";
 
const metadata = {
  appDeeplinkUrl: "https://your-app.example.com", // required to establish your app's identity, use 'https://' link for production
  appCustomScheme: "myapp://", // optional, used to remove the Done screen after signing
  appName: "My App Name",
  appChainIds: [8453],
  appLogoUrl: "https://example.com/logo.png",
};
 
export const config = createConfig({
  chains: [base],
  connectors: [
    createConnectorFromWallet({
      metadata,
      wallet: Wallets.CoinbaseSmartWallet,
    }),
  ],
  transports: {
    [base.id]: http(),
  },
});

Then you can use wagmi's react interface to interact with the Smart Wallet.

App.tsx

import { useConnect } from "wagmi";
 
// ...
 
const { connect, connectors } = useConnect();
 
return (
  <Button
    title={"Connect"}
    onPress={() => {
      connect({ connector: connectors[0] });
    }}
  />
);

Give feedback!

Send us feedback on the Coinbase Developer Platform Discord or create a new issue on the MobileWalletProtocol/react-native-client repository.