If you’re choosing between Supabase and Firebase for a new mobile app, the short answer is this: pick Firebase if your data is genuinely document-shaped and your team wants the most mature real-time mobile SDKs available today. Pick Supabase if your app has real relationships between its data, groups, members, permissions, anything with foreign keys, or your team already thinks in SQL. We made this exact call building Mativco, a group photo-sharing app for iOS and Android, and the data model is what decided it. Not a feature checklist, not a popularity contest.
What’s the Actual Difference Between Supabase and Firebase?
Firebase is built around Firestore, a NoSQL document database. Data lives in collections of documents, and you denormalize by design: a group chat app might store a copy of each member’s display name inside every message document, because Firestore isn’t built for joins. That’s fast to query and scales without much thought, but it means your data model and your UI structure end up tightly coupled from day one.
Supabase runs on Postgres. That’s the whole pitch, and it matters more than most comparison posts give it credit for. You get real foreign keys, real joins, and a schema you can actually look at and understand six months later without reverse-engineering which documents reference which other documents. For an app where “a group has many members who each upload many photos” is the entire product, that’s not a nice-to-have. It’s the data model writing itself.
Supabase also wraps that Postgres database in Row Level Security (RLS) for access control, instead of Firebase’s separate security rules language. RLS is a real Postgres feature, not a bolt-on syntax you learn only for this one platform, and it does the actual permission enforcement at the database layer rather than in application code you have to trust everywhere.
Pricing: Where the Difference Actually Shows Up
Every Supabase-vs-Firebase post online leads with pricing, and for good reason: the two platforms bill in fundamentally different shapes, not just different numbers.
| What You’re Paying For | Supabase Pro ($25/mo base) | Firebase Blaze (pay as you go) |
|---|---|---|
| Database | 8 GB disk included, then $0.125/GB | Firestore billed per read/write/delete operation, no flat disk allowance |
| Storage | 100 GB included, then $0.0213/GB | Cloud Storage: $0.026/GB stored, $0.12/GB downloaded |
| Auth / users | 100,000 MAUs included, then $0.00325/MAU | No equivalent flat MAU allowance; billed through connected services |
| Compute | $10/mo credit covers a Micro instance; scales up to $3,730/mo at the top tier | Cloud Functions: $0.40 per million invocations above 2M/month free |
Supabase’s Postgres pricing (confirmed on its own pricing page) is a flat base fee plus predictable per-GB overage. Firebase’s Blaze plan (per its official pricing page) bills per read, per write, and per delete on Firestore, which is genuinely hard to estimate before you’ve shipped and watched real usage patterns. A chatty app with lots of small document reads can rack up Firestore costs that a relational query batching the same data wouldn’t.
Neither model is “cheaper” in the abstract. A read-heavy, write-light app with predictable traffic can do fine on Firebase’s free Spark tier for a long time. An app with complex relational queries run often tends to cost less to reason about, if not always less in dollars, on Supabase.
Why We Picked Supabase for Mativco
Mativco is a consumer app we built for a client whose problem was simple to describe and annoying to live with: photos from a shared trip or event end up scattered across a dozen individual phone galleries and groups chats, and nobody can find them again a month later. The fix needed one shared place per group where members could upload, view, and contribute photos together. It’s the kind of brief that shows up often in our mobile app development work: the feature list sounds simple, and the data model underneath it is what actually decides the build.
That’s a relational problem wearing a social-app costume. A group has many members. A member belongs to many groups. Each group has many photos, each uploaded by a specific member, each visible only to that group’s members. Every one of those is a foreign key relationship, and Postgres handles that natively instead of asking you to fake it with document references and client-side joins.
We built it on Flutter and Dart for a single codebase across iOS and Android, with Supabase handling authentication (Google, Apple, and email sign-in), the Postgres database for groups, members, and invitations, and Row Level Security enforcing that a user can only see photos belonging to groups they’ve actually joined, at the database layer rather than trusting every client screen to check permissions correctly. Cloudinary handled image storage and transformation, since that’s a job a dedicated media CDN does better than either platform’s generic file storage. The whole build, from first screen to a working app on both platforms, took four weeks, which is the kind of turnaround a straightforward consumer SaaS product like this needs to validate before scope grows.
Could we have built the same app on Firebase? Sure. But every join we needed (show me every photo in groups this user belongs to, uploaded by members they haven’t blocked) would have meant either denormalizing that data into every document that needs it, or running multiple round-trip queries and stitching results together in application code. With Postgres, it’s one query with a join. That’s not a minor convenience on a four-week timeline. It’s the difference between shipping the feature and shipping a workaround for not having it.
Where Firebase Is Still the Better Call
None of this makes Supabase the universal right answer, and a comparison post that pretends otherwise isn’t being honest with you. Firebase earns the pick in a few specific situations.
- Real-time-heavy apps with simple data shapes. A live chat app, a multiplayer game lobby, or a live-location-sharing feature benefits from Firestore’s real-time listeners and Firebase’s years of mobile-specific tuning around exactly that use case.
- Teams with no SQL experience and a hard deadline. Firestore’s document model has a genuinely shorter learning curve for a team that’s never written a JOIN and isn’t going to start now.
- Apps that lean on Google’s broader mobile stack. Push notifications through FCM, crash reporting, and analytics are deeply integrated in Firebase in a way that takes extra wiring on Supabase.
- Offline-first apps with simple sync needs. Firestore’s offline persistence for mobile SDKs is mature and well-documented for straightforward read/write sync patterns.
If your app genuinely fits one of those four, the SQL-vs-NoSQL argument above doesn’t override it. Pick the tool that matches what the app actually needs to do, not whichever one sounds more serious in a sales conversation.
The Part Most Comparison Posts Skip: What This Means for AI Features Later
One thing that rarely makes it into Supabase-vs-Firebase roundups: if there’s any chance this app grows an AI feature later (semantic search over user content, a recommendation feed, a chatbot grounded in the app’s own data) Postgres has a real advantage most teams don’t realize until they need it. Extensions like pgvector let you store and query embeddings directly alongside your relational data, in the same database, with the same access controls. That’s relevant well beyond mobile apps; it’s the same reasoning that shapes a lot of our AI development work when a client’s data already lives in a relational structure and the AI feature needs to respect the same permission boundaries the rest of the app already enforces.
Firebase has no equivalent built into Firestore. You’d be standing up a separate vector database and keeping it in sync with your document store, which is exactly the kind of two-systems complexity Supabase avoids by putting it in the same Postgres instance you’re already running.
This is the same build-it-for-where-it’s-actually-going thinking we wrote about in our Flutter POS build: the framework and backend choices that look interchangeable on day one stop being interchangeable the moment the product needs something specific from them.
Frequently Asked Questions
Can I migrate from Firebase to Supabase later if I choose wrong?
Technically yes, but it’s a real migration project, not a config change. You’re moving from a document model to a relational schema, which means redesigning your data structure, not just copying records over. Budget for it like a mid-sized development project if you’re not confident in the choice upfront.
Is Supabase actually open source, or is that just marketing?
Supabase is genuinely open source and can be self-hosted, which is a real difference from Firebase’s closed, Google-only infrastructure. Most teams still use Supabase’s hosted platform for the managed infrastructure, but the self-hosting option is a real escape hatch if you ever need it.
Does Supabase support the same offline mobile experience as Firebase?
Not as a built-in SDK feature. Firebase’s offline persistence for Firestore is more mature out of the box. Supabase apps typically handle offline support with a local database (like SQLite via Drift or similar) and a custom sync layer, which is more work upfront but gives you more control over conflict resolution.
Which one is cheaper for a small app with under 10,000 users?
At small scale, Firebase’s free Spark tier is often cheaper or free, since Supabase’s Pro tier starts at a flat $25/month once you need features past the free tier’s limits. The cost comparison flips as usage and query complexity grow, which is why the right question isn’t “which is cheaper today” but “which is cheaper once this actually has users.”
Sources
Supabase pricing page, accessed for current Pro tier rates on database, storage, auth, and compute.
Firebase pricing page, accessed for current Spark and Blaze plan limits and overage rates.
