// the find
MetaMask/metamask-mobile
Mobile web browser providing access to websites that use the Ethereum blockchain
This is the official MetaMask mobile wallet — a React Native app for iOS and Android that handles Ethereum accounts, transaction signing, and dApp browsing. It's used by millions of people but has under 3k stars because most MetaMask mindshare lives in the browser extension repo. The codebase is maintained by a large team at Consensys and shows it.
The Expo development path is a real win: external contributors can skip native compilation entirely by downloading a prebuilt APK/IPA and just running the JS bundler, which cuts onboarding friction substantially for a project this complex. The CI pipeline is unusually mature — they have smart E2E test selection that avoids running the full suite on every PR, separate Detox and Appium test tracks, and performance regression testing via Reassure. The fitness functions in `.github/scripts/fitness-functions/` are a clever pattern: they encode architectural constraints (like the BigInt migration burndown allowlist) as CI checks rather than relying on reviewers to catch drift. The feature flag registry with automated drift detection prevents flags from going undocumented or getting stranded in the codebase indefinitely.
The `.yarn/patches/` directory has 20+ patches on third-party packages including `react-native` itself, `detox`, and multiple `@metamask/*` packages. That's a substantial maintenance burden that quietly bites you on every dependency upgrade. External contributor setup has several hard failure modes: you need your own Infura API key (without it the app can't connect to any network), you need a Firebase project configured with the exact package name `io.metamask` (which you cannot publish under), and the README directs internal contributors to grab secrets from 1Password — meaning the external path is genuinely second-class. The `yarn setup` postinstall is described as 'lengthy' and that's not underselling it given the native module count. Finally, the skills sync system (`yarn skills`) that pulls AI agent prompts from external repos at install time is a novel attack surface that most teams haven't thought through.