Mobile Development

Stack

Expo 54, React Native 0.81, expo-router (file-based routing), Tamagui v4 (UI), TypeScript strict mode.

Local Build Prerequisites

Required to run expo run:android or expo prebuild:

If expo run:android fails with a Java error:

brew install openjdk@17
export JAVA_HOME="$(brew --prefix openjdk@17)/libexec/openjdk.jdk/Contents/Home"
export PATH="$JAVA_HOME/bin:$PATH"

If expo run:android fails with ANDROID_HOME not set or SDK not found:

export ANDROID_HOME="$HOME/Library/Android/sdk"
export PATH="$ANDROID_HOME/emulator:$ANDROID_HOME/platform-tools:$PATH"

Both are set permanently by mise run install. If missing, re-run it or add to ~/.zshrc manually.

iOS builds require Xcode (App Store). No additional toolchain needed beyond Xcode.

Imports

Use @/ path alias for project root: @/lib/supabase, @/lib/posthog.

UI Components

Use Tamagui components with shorthand props. Never use raw React Native View/Text.

// ✅
import { YStack, XStack, Text, Button, Card, Spinner, ScrollView } from 'tamagui';

<YStack gap="$4" p="$4">
  <Text fos="$6" fow="bold">Title</Text>
  <Button>Action</Button>
</YStack>

// ❌
import { View, Text } from 'react-native';

Common shorthand: bg (background), p/px/py (padding), m/mt (margin), br (borderRadius), bw (borderWidth), boc (borderColor), fos (fontSize), fow (fontWeight), col (color), ai (alignItems), jc (justifyContent), gap, elevate, bordered.

Routing

File-based via expo-router:

• app/_layout.tsx — layout wrappers (Stack, Tabs)
• app/index.tsx — home screen
• app/settings.tsx — named route

Use Stack with headerShown: false (current convention).

New Screen

import { YStack, Text } from 'tamagui';

export default function MyScreen() {
  return (
    <YStack f={1} ai="center" jc="center" bg="$background">
      <Text>My Screen</Text>
    </YStack>
  );
}

Supabase

import { supabase } from '@/lib/supabase';

Single shared client. Uses EXPO_PUBLIC_SUPABASE_URL and EXPO_PUBLIC_SUPABASE_PUBLISHABLE_KEY.

Theme

Default theme is dark. TamaguiProvider wraps the app in _layout.tsx with defaultTheme="dark".

Environment Variables

All public config uses EXPO_PUBLIC_* prefix. Access via process.env.EXPO_PUBLIC_*.