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Is Mobile Auth free to use?

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Who published Mobile Auth?

tomevault-io (@tomevault-io) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Mobile Auth by tomevault-io — Agent Skill

Name: Mobile Auth
Author: tomevault-io

Mobile Auth

Better Auth integration with Expo/React Native. Use when working on mobile authentication, session management, or debugging auth issues in the mobile app. Triggers on "mobile auth", "expo auth", "better-auth expo", "session provider", "SecureStore", or when editing apps/frontend/mobile auth files. Use when this capability is needed.

tomevault-io 41730b6 2 files · 3.2 KB Updated Sep 17, 2026

File contents

Mobile Auth (Better Auth + Expo)

The mobile app uses Better Auth with @better-auth/expo plugin.

The Problem

Better Auth's session state doesn't sync reliably with React context on Expo. The plugin stores cookies in expo-secure-store, but reactive session updates don't propagate as expected.

Our Solution

Custom SessionProvider that:

Initializes from cache - Read cached session from SecureStore on app start
Subscribes to auth signals - Listen to $sessionSignal for auth state changes
Manual refresh - Call onAuthSuccess() after sign-in/sign-up

Reading Cached Session

// src/lib/auth.ts
export function getCachedSession(): AuthSession | null {
  const raw = SecureStore.getItem(SESSION_DATA_KEY);
  // validate and return
}

Session Provider

// src/providers/session-provider.tsx
useEffect(() => {
  const store = getAuthClient().$store;
  const sessionSignal = store.atoms.$sessionSignal;
  const unsubscribe = sessionSignal.subscribe(() => {
    setData(getCachedSession());
  });
  return () => unsubscribe();
}, []);

Required Configuration

Config	Value	Notes
`cookiePrefix`	`yourcompany`	Must match backend's `advanced.cookiePrefix`
`scheme`	`mobile`	Must match `scheme` in `app.json`
`storagePrefix`	`mobile`	Prefix for device storage keys

Key Files

Mobile auth client: apps/frontend/mobile/src/lib/auth.ts
Session provider: apps/frontend/mobile/src/providers/session-provider.tsx
Backend auth config: apps/backend/api/src/auth.ts

Known Issues

Session expiry detection relies on parsing expiresAt from cached data
$sessionSignal subscription is undocumented API and may change
Web platform falls back to standard cookie-based auth (no SecureStore)

Troubleshooting

Issue	Check
Session not updating	Verify `onAuthSuccess()` called after sign-in
Cookie mismatch	Compare `cookiePrefix` between mobile and backend
Auth redirect fails	Check `scheme` matches `app.json`

Converted and distributed by TomeVault — claim your Tome and manage your conversions.

---name: mobile-authdescription: Better Auth integration with Expo/React Native. Use when working on mobile authentication, session management, or debugging auth issues in the mobile app. Triggers on "mobile auth", "expo auth", "better-auth expo", "session provider", "SecureStore", or when editing apps/frontend/mobile auth files. Use when this capability is needed.---# Mobile Auth (Better Auth + Expo)The mobile app uses Better Auth with `@better-auth/expo` plugin.## The ProblemBetter Auth's session state doesn't sync reliably with React context on Expo. The plugin stores cookies in `expo-secure-store`, but reactive session updates don't propagate as expected.## Our SolutionCustom `SessionProvider` that:1. **Initializes from cache** - Read cached session from SecureStore on app start2. **Subscribes to auth signals** - Listen to `$sessionSignal` for auth state changes3. **Manual refresh** - Call `onAuthSuccess()` after sign-in/sign-up### Reading Cached Session```tsx// src/lib/auth.tsexport function getCachedSession(): AuthSession | null { const raw = SecureStore.getItem(SESSION_DATA_KEY); // validate and return}```### Session Provider```tsx// src/providers/session-provider.tsxuseEffect(() => { const store = getAuthClient().$store; const sessionSignal = store.atoms.$sessionSignal; const unsubscribe = sessionSignal.subscribe(() => { setData(getCachedSession()); }); return () => unsubscribe();}, []);```## Required Configuration| Config | Value | Notes ||--------|-------|-------|| `cookiePrefix` | `yourcompany` | Must match backend's `advanced.cookiePrefix` || `scheme` | `mobile` | Must match `scheme` in `app.json` || `storagePrefix` | `mobile` | Prefix for device storage keys |## Key Files- Mobile auth client: `apps/frontend/mobile/src/lib/auth.ts`- Session provider: `apps/frontend/mobile/src/providers/session-provider.tsx`- Backend auth config: `apps/backend/api/src/auth.ts`## Known Issues- Session expiry detection relies on parsing `expiresAt` from cached data- `$sessionSignal` subscription is undocumented API and may change- Web platform falls back to standard cookie-based auth (no SecureStore)## Troubleshooting| Issue | Check ||-------|-------|| Session not updating | Verify `onAuthSuccess()` called after sign-in || Cookie mismatch | Compare `cookiePrefix` between mobile and backend || Auth redirect fails | Check `scheme` matches `app.json` |---> Converted and distributed by [TomeVault](https://tomevault.io/claim/nikola-milovic) — claim your Tome and manage your conversions.

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