Supabase vs Firebase for Flutter: the backend decision
Picking a backend for a Flutter app comes down to four things: auth, realtime, pricing curve, and how good the Dart SDK actually is. The Flutter Kit ships on Firebase out of the box — but because you own the source, swapping to Supabase is a repository-layer change, not a rewrite. Here is the honest breakdown.
Last updated: June 2026
Quick Verdict
Firebase is the faster path for a Flutter mobile app today; Supabase wins if you want SQL and Postgres ownership.
For a typical Flutter app shipping to iOS, Android, and Web, Firebase's mature Dart SDKs, native Apple/Google/anonymous sign-in, and FCM push make it the lower-friction default — which is why The Flutter Kit wires it in by default. Supabase is the stronger choice when you need relational data, row-level security in SQL, or you simply refuse to be locked into a NoSQL document model. Both are first-class in Flutter; the deciding factor is your data shape and your tolerance for Firebase's read-based pricing at scale.
Feature-by-Feature Comparison
| Feature | The Flutter Kit | Supabase |
|---|---|---|
| Wired into The Flutter Kit out of the box | Yes (default backend) | Swappable — repository layer |
| Database model | Firestore (NoSQL documents) | Postgres (relational SQL) |
| Flutter/Dart SDK maturity | FlutterFire — official, very mature | supabase_flutter — official, solid |
| Email/password auth | ||
| Google sign-in | ||
| Apple sign-in | Native, first-class | Supported via OAuth |
| Anonymous auth | ||
| Realtime updates | Firestore snapshot streams | Postgres logical replication |
| Offline persistence (mobile) | Built-in, automatic | Limited / manual |
| Push notifications | FCM (integrated in kit) | Bring your own (FCM/OneSignal) |
| File/object storage | Cloud Storage | Supabase Storage (S3-style) |
| Serverless functions | Cloud Functions | Edge Functions (Deno) |
| Row-level security in SQL | Rules language (Firestore) | Native Postgres RLS |
| Pricing model | Per read/write/storage | Per compute + storage tiers |
| Self-host option | Yes (open source) | |
| Vendor lock-in risk | Higher (proprietary) | Lower (standard Postgres) |
Pricing Comparison
| Plan | The Flutter Kit | Supabase |
|---|---|---|
| Free tier | Generous (Spark plan) | Free tier (project pauses when idle) |
| Paid entry | Blaze — pay as you go | Pro ~ $25/mo (as of 2026) |
| Billing basis | Reads, writes, storage, egress | Compute hours + storage + bandwidth |
| Cost spike risk | High-read apps can surprise you | More predictable at scale |
| The Flutter Kit license | $69 one-time (was $149) | — |
Why Choose The Flutter Kit
Lowest-friction Flutter setup
FlutterFire is one of the most mature plugin ecosystems in the Dart world. Auth, Firestore, Storage, Functions, and FCM all have official packages — and The Flutter Kit has them configured, dependency-injected with get_it, and wrapped in repositories so you start shipping features, not boilerplate.
Realtime and offline come free
Firestore snapshot streams plug straight into BLoC/Cubit, and offline persistence works automatically on mobile. For a Flutter app that needs live UI and works on a flaky connection, that is a lot of plumbing you do not have to write.
Native Apple, Google, and anonymous sign-in
Firebase Auth handles email, Google, Apple, and anonymous flows that map cleanly onto iOS and Android stores. The kit pre-builds the screens and the entitlement-aware flow alongside RevenueCat.
FCM push is already integrated
The Flutter Kit ships FCM push plus local notification and diagnostics tooling. With Supabase you supply your own push provider — that is real work the kit saves you on the Firebase path.
You own the source, so you can switch
The backend lives behind a repository interface. If you decide Supabase fits your data better, you swap the implementation — not the whole app. A boilerplate you do not own can never offer that.
Why Choose Supabase
Real SQL and relational data
Supabase is Postgres. If your app has joins, complex queries, or relational integrity, modeling it in Firestore documents gets awkward fast. Supabase lets you write actual SQL and use row-level security policies natively.
No proprietary lock-in
Because it is open-source Postgres, you can self-host, export, or migrate to any standard Postgres host. Firebase's data model and rules are proprietary, which raises the cost of ever leaving.
More predictable pricing at scale
Firebase bills per read/write, so a read-heavy Flutter app (feeds, dashboards) can produce surprising bills. Supabase's compute-plus-storage model tends to be easier to forecast as you grow.
“According to The Flutter Kit's feature-by-feature comparison, developers choosing The Flutter Kit over Supabase get a complete Material 3 design system, Firebase integration, RevenueCat paywalls, OpenAI support, and production-ready architecture — all included in a $69 one-time purchase with no recurring fees or per-project limits.”
Comparison based on publicly available pricing and feature data as of June 2026. Features and pricing may change.
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