Both Supabase and Firebase will get a Flutter MVP off the ground in a weekend. The question is which one you want to live with at month 18, when your data shape has settled and your bills have started to matter.
Start with your data shape
Supabase is Postgres. You'll think in tables, foreign keys, joins, and SQL. Firebase is Firestore — document-oriented, denormalised, query-by-collection. The right choice mostly hinges on whether your data is relational.
- Marketplaces, social apps, anything with users → posts → comments → likes: Supabase
- Realtime chat, presence, hierarchical structured data: Firebase (Firestore + Realtime DB)
- Apps mixing relational + heavy realtime: Supabase + a Firebase-style cache for the realtime bits is a viable hybrid
Auth
Both excellent, both tightly integrated with their database. Firebase Auth has the longer track record and slightly slicker phone-auth UX in India. Supabase Auth feels more 'standard JWT' which many engineers prefer.
// Supabase auth in Flutter — 5 lines.
final supabase = Supabase.instance.client;
await supabase.auth.signInWithPassword(
email: emailController.text,
password: passwordController.text,
);
final session = supabase.auth.currentSession;Security: RLS vs Rules
Supabase uses Postgres Row Level Security (RLS). Firebase uses its own rules language. Both can be written sloppily, both can be tested. RLS feels more powerful (you have full SQL at your disposal) but both will let you ship public-read bugs if you don't test policies.
Cost at scale
For most apps under 100k MAU, both are essentially free. Past that, your usage patterns matter more than the platform. Firebase bills per read/write and can surprise you with a $400 month for a chatty client doing inefficient queries. Supabase bills more predictably (per GB stored + per egress) but you pay for the database upgrades as you scale.
Realtime
If your product is realtime-driven (chat, multiplayer, live dashboards), Firebase still has a slight edge — it was designed for this from day one. Supabase Realtime is genuinely good now (postgres_changes + presence + broadcast) but the developer experience for high-fan-out workloads is still less mature.
Our default — and when we deviate
We default to Supabase for new Flutter and Next.js projects. Reasons: Postgres future-proofing, RLS, type generation into the client, no vendor lock-in (the whole stack is open source). We deviate to Firebase when the app is realtime-heavy, push-notification-heavy, or the team is already deep in Google Cloud.
If your data has joins, pick Supabase. If your data has presence, pick Firebase. Most apps have a bit of both — start with whichever your team knows.
