Ionic Firebase

Firebase (Auth + Firestore)

The default backend for most Ionic apps. Auth handles sign-up / sign-in (including social providers); Firestore handles persistent data with realtime sync and offline support.

When to consult

• Project setup + native config files (google-services.json, GoogleService-Info.plist): [setup.md](references/setup.md)
• Auth (email, Google, Apple, magic link): [auth.md](references/auth.md)
• Firestore (read/write/realtime/offline): [firestore.md](references/firestore.md)
• Per-framework integration snippets: [framework-snippets.md](references/framework-snippets.md)

Library choice

Two viable approaches:

| Approach | When to pick | |----------|--------------| | Firebase JS SDK (firebase npm package) | Web-first, simple cases, web/mobile parity. Works in browser, iOS WKWebView, Android WebView. Auth popups can be tricky on native. | | Capacitor Firebase plugins (@capacitor-firebase/*) | Native auth dialogs (Google sign-in via native sheets), offline Firestore via native SDKs, push via native FCM. More setup, much better UX. |

Recommendation: use the JS SDK for v1 (faster), migrate to @capacitor-firebase/* plugins when you hit native UX gaps (especially Google Sign-In, which is rough via web-only on Android).

This skill covers both — pick whichever fits.

Hard rules

• ✅ Never put Firebase Admin SDK code in the app. That's server-only — uses a service account with full permissions.
• ✅ Firebase web config (apiKey, projectId, etc.) is safe to ship — Security Rules do the gating. See [../ionic-shared/references/environments-and-keys.md](../ionic-shared/references/environments-and-keys.md).
• ✅ Write Firestore Security Rules before going live. The default "test mode" rules expire after 30 days and become "deny all" if not replaced.
• ❌ Don't use Realtime Database for new projects unless you have a specific reason — Firestore is the modern choice.
• ❌ Don't query a collection with no index expecting it to scale — Firestore's query patterns require composite indexes for compound filters.

Library

npm install firebase
# OR for native plugins:
npm install @capacitor-firebase/app @capacitor-firebase/authentication @capacitor-firebase/firestore
npx cap sync

Pairs with

• Push notifications via FCM: Firebase's google-services.json / GoogleService-Info.plist also covers FCM. Wire push handling itself via [../ionic-shared/references/push-notifications.md](../ionic-shared/references/push-notifications.md) — the plugin (@capacitor/push-notifications) is independent of Firebase Auth/Firestore but uses the same native config files.
• Magic-link sign-in: requires Universal Link / App Link plumbing — see [../ionic-deep-links/](../ionic-deep-links/SKILL.md). Firebase Dynamic Links is shut down — your own deep-link infra is the path.
• Sign in with Apple: integrates via @capacitor-firebase/authentication (this skill, [auth.md](references/auth.md)). Don't also install @capacitor-community/apple-sign-in — see [../ionic-apple-sign-in/SKILL.md](../ionic-apple-sign-in/SKILL.md) for when to use the standalone plugin instead.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: erkamyaman
• Source: erkamyaman/ionic-capacitor-skills
• License: MIT
• Homepage: https://www.skills.sh/erkamyaman/ionic-capacitor-skills

Install and usage instructions live in the source repository linked above.