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MetaMask is a mobile wallet that provides easy access to websites that use the Ethereum blockchain.
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To learn how to develop MetaMask-compatible applications, visit our Developer Docs.
To learn how to contribute to the MetaMask codebase, visit our Contributor Docs.
- Architecture
- Expo Development Environment Setup
- Native Development Environment Setup
- Build Troubleshooting
- Testing
- Debugging
- API Call Logging for Debugging
- Storybook
- Miscellaneous
Expo is the fastest way to start developing. With the Expo framework, developers don't need to compile the native side of the application as before, hence no need for any native environment setup, developers only need to download a precompiled development build and run the javascript bundler. The development build will then connect with the bundler to load the javascript code.
Install node, yarn and watchman.
git clone git@github.com:MetaMask/metamask-mobile.git && cd metamask-mobile
yarn setup:expo
yarn watch
- Access Runway via Okta and go to the Expo bucket either on the iOS or Android section. From there you will see the available development builds (android-expo-dev-build.apk or ios-expo-dev-build.ipa).
- For Android:
- Install the .apk on your Android device or simulator.
- For iOS:
- Device: you need to have your iPhone registered with our Apple dev account. If you have it, you can install the .ipa on your device.
- Simulator: please follow the native development section and run
yarn setupandyarn start:iosas the .ipa will not work for now, we are working on having an .app that works on simulators.
[SOON] For external developers (we are testing the new dev builds and will make them publicly available soon after)
If on a simulator:
- use the initial expo screen that appears when starting the development to choose the bundler url
- OR press "a" for Android or "i" for iOS on the terminal where the bundler is running
If on a physical device:
- Use the camera app to scan the QR code presented by the bundler running on the terminal
That's it! This will work for any javascript development, if you need to develop or modify native code please see the next section.
If developing or modifying native code or installing any library that introduces or uses native code, it is not possible to use an Expo precompiled development build as you need to compile the native side of the application again. To do so, please follow the steps stated in this section.
Before running the app for native development, make sure your development environment has all the required tools. Several of these tools (ie Node and Ruby) may require specific versions in order to successfully build the app.
Setup your development environment
Clone the project
git clone git@github.com:MetaMask/metamask-mobile.git && cd metamask-mobile
MetaMask uses Firebase Cloud Messaging (FCM) to enable app communications. To integrate FCM, you'll need configuration files for both iOS and Android platforms.
- Grab the
.js.envfile from 1Password, ask around for the correct vault. This file contains theGOOGLE_SERVICES_B64_ANDROIDandGOOGLE_SERVICES_B64_IOSsecrets that will be used to generate the relevant configuration files for IOS/Android. - Install and run & start the application as documented below.
As an external contributor, you need to provide your own Firebase project configuration files:
GoogleService-Info.plist(iOS)google-services.json(Android)
- Create a Free Firebase Project
- Set up a Firebase project in the Firebase Console.
- Configure the project with a client package name matching
io.metamask(IMPORTANT).
- Add Configuration Files
- Create/Update the
google-services.jsonandGoogleService-Info.plistfiles in: android/app/google-services.json(for Android)ios/GoogleServices/GoogleService-Info.plistdirectory (for iOS)
- Create/Update the
- Create the correct base64 environments variables.
# Generate Android Base64 Version of Google Services export GOOGLE_SERVICES_B64_ANDROID="$(base64 -w0 -i ./android/app/google-services.json)" && echo "export GOOGLE_SERVICES_B64_ANDROID="$GOOGLE_SERVICES_B64_ANDROID"" | tee -a .js.env # Generate IOS Base64 Version of Google Services export GOOGLE_SERVICES_B64_IOS="$(base64 -w0 -i ./ios/GoogleServices/GoogleService-Info.plist)" && echo "export GOOGLE_SERVICES_B64_IOS="$GOOGLE_SERVICES_B64_IOS"" | tee -a .js.env
[!CAUTION]
In case you don't provide your own Firebase project config file or run the steps above, you will face the error
No matching client found for package name 'io.metamask'.
In case of any doubt, please follow the instructions in the link below to get your Firebase project config file. Firebase Project Quickstart
yarn setup
Not the usual install command, this will run scripts and a lengthy postinstall flow
Run Metro bundler
yarn watch
Like a local server for the app
Run on a iOS device
yarn start:ios
Run on an Android device
yarn start:android
