Supabase vs Firebase: Which Backend for Your First App?

If you build with AI tools, you'll run into two "backend-as-a-service" platforms again and again: Supabase, which Lovable and Bolt integrate with, and Google's Firebase, which powers countless tutorials and mobile apps. Both give you a database, login, file storage, and serverless functions without running a server. They make different bets.

The one-line difference

Supabase is built around PostgreSQL — a relational SQL database — and open-source tools.
Firebase is built around Firestore — a NoSQL document database — and Google Cloud.

Almost every other difference follows from that. (SQL vs NoSQL explains the underlying choice.)

Side by side

	Supabase	Firebase
Main database	PostgreSQL (tables, SQL)	Firestore (documents, collections)
Queries	Full SQL: joins, aggregates, reports	Simpler queries; joins done in your code
Security	Row-level security policies in SQL	Security Rules in Firebase's own language
Auth	Email, magic links, social logins, phone	Email, social logins, phone, anonymous
Real-time	Subscribe to database changes	Real-time sync is a core strength, with offline support
File storage	Yes	Yes
Functions	Edge Functions (Deno/TypeScript)	Cloud Functions (Node.js, Python)
Open source / self-hostable	Yes	No
Pricing shape	Per project tiers, plus usage	Free tier, then pay per read/write/storage
Best-known strength	SQL power and portability	Mobile SDKs, offline sync, Google ecosystem

Where Supabase fits better

Relational data — users, orders, teams, permissions — which describes most business apps.
Reporting and complex queries — anything you'd want to answer with SQL.
Avoiding lock-in. It's standard Postgres underneath. You can export your data with standard tools and move it to any Postgres host.
AI tools write it well. SQL and Postgres are extremely well represented in what models have learned.

Where Firebase fits better

Mobile apps, especially with offline use — Firebase's SDKs sync data when the connection returns.
Real-time collaborative features — chat, live dashboards, presence.
Deep Google integration — Analytics, Crashlytics, push notifications, Google Cloud.
Data that's naturally documents rather than related tables.

Security: the thing to get right on either

Both platforms let your front end talk directly to the database. That's convenient, and it means the database's own security rules are the only thing standing between any visitor and your data.

On Supabase, that's row-level security (RLS). If it's switched off on a table, anyone with your public key can read or change everything in it. (Supabase Row-Level Security Explained.)
On Firebase, it's Security Rules. Rules left in "test mode" — allowing all reads and writes — are a well-known cause of data leaks.

AI-generated apps get this wrong on both platforms. Whichever you choose, check the rules before launch. (A Security Checklist for Vibe-Coded Apps.)

Pricing: watch the shape, not just the number

Both have free tiers good enough to build and test.

Supabase charges mainly per project and plan, plus usage over the included limits. Free projects are paused after a period of inactivity.
Firebase charges per document read, write, and delete, plus storage and bandwidth. That's very cheap at small scale, but a page that reads thousands of documents per view — or a bug that loops — can run up costs quickly.

Set budget alerts on either. (How Much Does It Cost to Run an App?.)

Lock-in and moving later

This matters more than people expect.

Leaving Supabase is relatively straightforward: dump the Postgres database and restore it anywhere. Auth and storage need more work, but the data is portable. (Postgres Backup and Restore.)
Leaving Firebase usually means reshaping your data from documents into another model and rewriting data-access code, because Firestore's API and model are unique to it.

So which one?

Web app with users, accounts, and related data? Supabase is the more natural fit.
Mobile-first, offline, or heavily real-time app? Firebase has the edge.
Already built on one? Stay unless you have a concrete problem. Migrating a working app is rarely worth it just for the sake of it.

Either way, you can outgrow the "backend in the browser" model. Many apps eventually add their own server for payments, webhooks, background jobs, and secrets — which both platforms support connecting to. (Frontend vs Backend.)

EasySpawn gives each project a managed Postgres database and a real backend that runs all the time — a natural next step when your Supabase- or Firebase-based app needs server-side code, workers, or more control. See how it works for AI-built apps or join the waitlist.