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
• Development Environment Setup
• Build Troubleshooting
• Testing
• Debugging
• Storybook
• Miscellaneous

Before running the app, 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

Firebase Messaging Setup

Before running the app, keep in mind that MetaMask uses FCM (Firebase Cloud Message) to empower communications. Based on this, as an external contributor you would preferably need to provide your own FREE Firebase project config file with a matching client for package name io.metamask, and update your google-services.json file in the android/app or GoogleService-Info.plist file in the ios directory.

External Contributors In case you don't have FCM account, you can use ./android/app/google-services-example.json for Android or ./ios/GoogleServices/GoogleService-Info-example.plist for iOS and follow the steps below to populate the correct environment variables in the .env files (.ios.env, .js.env, .android.env), adding GOOGLE_SERVICES_B64_ANDROID or GOOGLE_SERVICES_B64_IOS variable depending on the environment you are running the app (ios/android).

Internal Contributors

We should access the Firebase project config file from 1Password.

The value you should provide to GOOGLE_SERVICES_B64_ANDROID or GOOGLE_SERVICES_B64_IOS is the base64 encoded version of your Firebase project config file, which can be generated as follows:

For Android

export GOOGLE_SERVICES_B64_ANDROID="$(base64 -w0 -i ./android/app/google-services-example.json)" && echo "export GOOGLE_SERVICES_B64_ANDROID=\"$GOOGLE_SERVICES_B64_ANDROID\"" | tee -a .js.env .ios.env

For iOS

export GOOGLE_SERVICES_B64_IOS="$(base64 -w0 -i ./ios/GoogleServices/GoogleService-Info-example.plist)" && echo "export GOOGLE_SERVICES_B64_IOS=\"$GOOGLE_SERVICES_B64_IOS\"" | tee -a .js.env .ios.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

Install dependencies

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