Supabase vs Firebase — which one for what

The two BaaS platforms every technical founder shortlists. Both work. Both have loud fanbases. Both have real weaknesses. We ship on both — and the choice depends less on the platforms and more on the shape of your product.

Here’s the honest split.

The one-line rule

• Supabase if your data is relational and you’ll eventually want SQL access
• Firebase if your data is real-time-heavy, consumer-facing, and you never want to think about SQL

Everything else is nuance.

Where Supabase wins

1. Relational data

Supabase is Postgres. Full SQL. Foreign keys. Joins. Views. Migrations. Everything you know about relational databases works.

Firebase’s Firestore is document-based. Joining collections requires client-side work or Cloud Functions. Fine for simple cases, painful for anything with more than 4-5 related entities.

Verdict: If your data model has any of users → orders → items, products → variants → inventory, or teachers → classes → students — use Supabase.

2. Row-level security (RLS)

Supabase RLS lets you write access rules in SQL, enforced at the database. Multi-tenant SaaS with per-user data isolation is a one-liner.

Firebase Security Rules are its own DSL. Fine for simple rules. Painful when they get complex.

Verdict: For multi-tenant SaaS, Supabase RLS is state of the art.

3. Cost transparency

Supabase pricing is boring: dollars per gigabyte, dollars per compute unit, dollars per user. You can predict your bill.

Firebase pricing has a lot of “read” and “write” units. First few thousand free, then it compounds fast in unexpected ways.

Verdict: For anything with predictable data patterns, Supabase costs less at scale. Firebase is cheaper for the first 3 months and more expensive from month 6.

4. Portability

Supabase is Postgres. You can leave. Export your database, run it on Neon, RDS, DigitalOcean, on-prem — anywhere.

Firebase is Google Cloud specific. Migration is painful.

Verdict: If long-term platform independence matters, Supabase.

Where Firebase wins

1. Real-time out of the box

Firestore’s real-time sync is best in class. Chat apps, live dashboards, multiplayer state — Firebase ships this natively.

Supabase Realtime works but requires more setup and has more edge cases.

Verdict: Chat, live dashboards, collaborative apps → Firebase.

2. Mobile SDKs

Firebase’s iOS + Android SDKs are the mature choice for mobile. Push notifications, remote config, A/B testing, crash reporting — all pieces work together.

Supabase’s mobile story has improved but isn’t the same depth of integrated tooling.

Verdict: Native or Flutter mobile app where FCM push, Remote Config, and Firebase Analytics all matter → Firebase.

3. Offline-first

Firestore syncs offline. Change data while offline, syncs when back online. This is a huge win for field apps, delivery apps, and Tier-2/Tier-3 usage.

Supabase requires you to build offline handling yourself.

Verdict: Field-force apps, delivery apps, offline-critical → Firebase.

4. First 3 months of a small app

Firebase has a generous free tier and cheap onboarding. If you’re building a consumer app with fewer than 50k users, Firebase is easy and free-ish.

Supabase has similar generosity but the value shows more at scale.

Verdict: MVP prototypes and small consumer apps → either is fine.

The head-to-head grid

Feature	Supabase	Firebase
Data model	Postgres (relational)	Firestore (document)
SQL access	Yes, full	No
Real-time	Yes, but with limits	Best in class
Auth	Yes, email + OAuth + magic link	Yes, richer providers
Storage	Yes, S3-compatible	Yes, own SDK
Serverless functions	Edge Functions (Deno)	Cloud Functions (Node)
Mobile SDK maturity	Improving	Best in class
Offline sync	DIY	Built in
Multi-tenant RLS	Best in class	Fine
Push notifications	Not first-class	FCM built in
Analytics	Integration required	Built in
Cost predictability	High	Low
Portability	High (it’s Postgres)	Low (lock-in)
Free tier	Generous	Generous

The projects we ship on Supabase

• SaaS platforms with real user data (Cortix, Posteri)
• Admin dashboards for D2C or B2B
• Multi-tenant apps with row-level isolation
• Anything where the client will eventually want direct SQL access
• Web-first products with a mobile companion

The projects we ship on Firebase

• Consumer mobile apps with real-time features
• Nonprofits and marketing platforms where content flow matters (Trivarna)
• Field-force apps that need offline-first
• Any app that’s mostly Android with FCM push as a core feature
• Prototypes we know will stay under 10k users for a while

The projects where we’ve regretted the choice

• Supabase for a chat-heavy consumer app → the real-time story was harder than needed
• Firebase for a multi-tenant SaaS → security rules got unmaintainable
• Both are fine choices with the wrong shape of product

The lock-in question

Neither platform locks you in badly if you build with clean abstractions from day one. But:

• Supabase is easier to migrate off because Postgres is Postgres
• Firebase is harder to migrate off because of Firestore’s document model

If migration matters — enterprise clients often want the option — bias Supabase.

The pricing math at scale

At 100k monthly active users with moderate reads/writes:

• Supabase: $200-400/month (depends on database size + compute)
• Firebase: $400-1200/month (depends heavily on read/write patterns)

Firebase costs can spike unexpectedly if a badly-written query does 1M reads. Supabase costs are more predictable because you can profile the SQL.

The one thing that beats the choice

Whichever you pick, abstract the database layer in your app code. Put a repository or service layer between your app and the BaaS SDK. If you migrate in 18 months, you rewrite one file, not fifty.

Both platforms are excellent. Pick the one that fits your product shape, and don’t lose sleep over it.