Quick verdict
Pick Supabase for SQL-shaped data, multi-tenant apps with row-level security, and the simplest Expo integration. Pick Firebase for document/realtime-tree data, huge free-tier auth, and when your team already lives in Google Cloud.
What each actually is
Supabase is an open-source backend-as-a-service on top of Postgres. Auth, a SQL database with row-level security (RLS), object storage, realtime over websockets, and edge functions. You can self-host the whole stack if you ever need to.
Firebase is Google’s managed backend-as-a-service. Auth, Firestore (document database), Realtime Database (JSON tree), Cloud Functions, and Cloud Storage. Mature, battle-tested, and deeply integrated with the broader Google Cloud ecosystem.
Head-to-head comparison
| Dimension | Supabase | Firebase |
|---|---|---|
| Database | Postgres (SQL) | Firestore (doc) / RTDB (tree) |
| Query shape | Full SQL + joins | Document / path-based |
| Row-level security | Yes, built in | Via rules (less expressive) |
| Auth | Email, OAuth, passkeys (beta) | Email, OAuth, phone |
| Expo integration | Managed workflow supported | Config plugin required |
| Realtime | Postgres changes over WebSocket | Native realtime (mature) |
| Pricing (free tier) | 500MB DB, 50k MAU, 1GB storage | 50k MAU, generous reads |
| Open source / self-host | Yes | No |
| Lock-in risk | Low (standard Postgres) | Medium (proprietary DB) |
Where Supabase wins
- SQL-shaped data. Users, posts, follows, comments — relational data wants joins, not nested paths.
- Multi-tenant apps. Row-level security makes workspace-scoped queries trivial and safe. See How to Build a SaaS Mobile App with AI.
- Expo managed workflow. Drop in
@supabase/supabase-jsand you are done. - Portability. Standard Postgres — you can move off Supabase later without rewriting your queries.
- Pricing clarity. Predictable scaling; no surprise $10k Firestore bills.
Where Firebase wins
- Mature realtime. Firebase Realtime Database and Firestore realtime are battle-tested at huge scale.
- Free auth at scale. 50k MAUs free and generous reads make it attractive for consumer apps.
- Google ecosystem. Analytics, Remote Config, Cloud Messaging, App Check — one project, one dashboard.
- Document-shaped data. If your data fits naturally as documents (chat messages, events, journal entries), Firestore is elegant.
- Maturity. 10+ years of production hardening across millions of apps.
Expo integration, side by side
The meaningful difference for Expo teams in 2026:
- Supabase: works with
@supabase/supabase-jsin managed Expo. Install and go. Works inside Expo Go for most features. - Firebase: needs
@react-native-firebase/appwith its config plugin. Will not work in Expo Go — you need a development build. Auth-only setups can use the JS SDK directly, but most serious apps end up on React Native Firebase.
Pricing at the next stage
MVP-stage apps are free on both. At 10k–100k MAUs:
- Supabase Pro: $25/month base, includes 8GB DB and 100GB transfer. Scales predictably by usage add-ons.
- Firebase Blaze: pay-as-you-go. Auth stays free up to 50k MAU; Firestore costs scale with reads/writes and can balloon if you do not structure queries carefully.
- Firebase is cheaper for auth-heavy apps with few reads. Supabase is cheaper and more predictable for read-heavy apps.
When to switch
Switching backends is painful — pick carefully up front. Migrate if: (1) your Firestore bill becomes unpredictable, (2) you need SQL joins Firestore cannot express, (3) you want to self-host for compliance. Migrate from Supabase if: (1) you need Firebase-ecosystem features that do not have Supabase equivalents, or (2) you already use Google Cloud heavily. For most apps generated via ShipNative, Supabase is the sensible default.