Arrivo

A ride-hailing app built on top of Turborepo monorepo: an Expo / React Native mobile app and an Express + TypeScript API.

Repository layout

arrivo/
├── apps/
│   ├── api/        Express 5 + TypeScript backend
│   └── mobile/     Expo (React Native) app
├── packages/       reserved for shared code (currently empty)
├── .husky/         git hooks
├── commitlint.config.mjs
├── pnpm-workspace.yaml
└── turbo.json

• apps/api: backend setup, environment variables, endpoints
• apps/mobile: mobile app setup, styling, components

Requirements

• Node.js 22.13 or newer
• pnpm 11 (npm i -g pnpm). The repo pins the package manager through devEngines, so pnpm fetches the declared version if yours differs.
• Git
• Android Studio with at least one Android Virtual Device (AVD)

Android environment

ANDROID_HOME must point at your Android SDK, and platform-tools and emulator must be on your PATH. On Windows the default SDK location is %LOCALAPPDATA%\Android\Sdk.

Verify in a fresh terminal:

echo $ANDROID_HOME
adb --version
emulator -list-avds

Getting started

pnpm install
cp apps/api/.env.example apps/api/.env

Start an emulator (Android Studio → Device Manager, or emulator -avd <name>), wait for it to finish booting, then use two terminals:

pnpm api

pnpm android

The first pnpm android run asks to install the Expo Go version matching the project's SDK on the emulator. Answer yes.

Check the API:

curl http://localhost:4000/health

Scripts

Run from the repository root.

Command	What it does
pnpm api	Start the API in watch mode
pnpm android	Start Expo and open the app on the Android emulator
pnpm lint	ESLint in every package
pnpm typecheck	TypeScript check in every package
pnpm test	Run tests in every package
pnpm build	Build every package that has a build script
pnpm format	Format the whole repo with Prettier
pnpm format:check	Check formatting without writing

Run the mobile app in its own terminal. Expo's interactive keys don't work well when started through Turborepo.

Git hooks

Installed automatically by pnpm install (the prepare script runs Husky).

Hook	Runs
pre-commit	lint-staged: ESLint (--fix) and Prettier on staged files, per app
commit-msg	commitlint: Conventional Commits format
pre-push	pnpm typecheck
Commit messages must look like type(scope): subject, for example feat(api): add rider endpoint. Valid types: feat, fix, docs, style, refactor, perf, test, build, ci, chore, revert.
git commit --no-verify skips the hooks. Don't rely on hooks alone to protect the main branch.

Things that will bite you

• Use pnpm, not npm, at the repo root. The root package.json declares pnpm in devEngines, so npm pkg set and similar commands fail with EBADDEVENGINES.
• pnpm 11 blocks dependency build scripts by default. If an install ends with ERR_PNPM_IGNORED_BUILDS, run pnpm approve-builds in Windows Terminal or PowerShell (the picker is interactive), then pnpm install. Approvals are stored in pnpm-workspace.yaml under allowBuilds.
• pnpm settings live in pnpm-workspace.yaml, not .npmrc. nodeLinker: hoisted is set there on purpose because Metro and pnpm's default layout don't get along.
• Tailwind must stay on 3.x. The mobile app uses NativeWind v4, which does not work with Tailwind 4. Never run pnpm add tailwindcss@latest.
• The mobile app is pinned to Expo SDK 57. NativeWind 4.2.7 supports the SDK 57 toolchain; compatibility with SDK 58 has not been verified. Don't upgrade the SDK without checking NativeWind first.
• Clear the Metro cache after changing metro.config.js, tailwind.config.js, babel.config.js or global.css: pnpm --filter @arrivo/mobile exec expo start --android --clear.
• The Android emulator reaches your computer at 10.0.2.2, not localhost.
• Line endings are forced to LF by .gitattributes. Without it, Windows checkouts flip files to CRLF and format:check fails.