Supabase vs Firebase for an app built with AI tools

For most web apps built with Lovable, Bolt, v0 or Cursor, Supabase is the easier fit: it's a Postgres database with SQL, Row Level Security and the integrations those tools already use. Firebase tends to fit better for mobile-first apps that need offline sync, for FlutterFlow projects and for apps built inside Google's tools. The right choice depends on the shape of your data, the tool you build with and who will maintain it, more than on which one is "better".

This guide compares the two where it matters for an AI-built app: data model, security, free tiers, pricing, the tools that default to each, and what moving later involves.

How do they compare at a glance?

Firebase also offers Data Connect, which puts a PostgreSQL database (Cloud SQL) behind Firebase. It's a different product with its own pricing; most AI-built Firebase apps use Firestore.

Which one does my AI tool use?

Often the tool decides before you do.

• Lovable and Bolt connect to Supabase directly, which is why so many AI-built web apps run on it.
• FlutterFlow has deep Firebase integration (it also supports Supabase). Firestore security rules are a common weak spot there; see Firebase security rules in FlutterFlow.
• Google AI Studio builds apps with Cloud Firestore and Firebase Authentication built in.
• Firebase Studio is being shut down. Google's migration page says new workspaces were disabled on June 22, 2026 and the platform closes on March 22, 2027. Firestore, Authentication and App Hosting themselves are not affected; if your project lives in Firebase Studio, move the code out before the deadline.
• Cursor, Claude Code and Replit will use whichever you ask for.

Switching away from your builder's default usually means losing its one-click setup, so it's a real cost to weigh.

How is the data model different?

Supabase stores data in tables with columns, relationships and joins. If your app has customers, orders, invoices and products that reference each other, SQL expresses that naturally, and reporting queries are easy.

Firestore stores documents in collections. It's fast and flexible for data you read in the same shape you write, like a chat thread or a user's settings, and it syncs to devices in real time with offline support. It's weaker at questions that cut across collections ("total revenue per customer last month"), which often means duplicating data or exporting it elsewhere.

A rough rule: if you can sketch your data as a spreadsheet with linked tabs, Supabase will feel natural. If it's mostly per-user documents that must work offline on phones, Firestore will.

How does security differ?

Both are safe when configured well and dangerous when left open, and an AI tool can leave either one open.

• Supabase: your front end talks to the database with a public key, and RLS policies decide what each user can do. A table without RLS, or with a using (true) policy, is readable by anyone. See is the Supabase anon key safe?
• Firebase: Security Rules decide what each request can read and write. Projects started in test mode allow everything for a period, and rules such as allow read, write: if true; sometimes survive into production.

Supabase policies are SQL, which most developers can read and test with ordinary database tools. Firebase rules are their own language, tested with the Firebase emulator. Neither is harder in principle; what matters is that someone reviews them.

How do the free tiers and pricing compare?

From each vendor's pricing page as of October 2026:

• Supabase Free: 500 MB database per project, 50,000 monthly active users, 1 GB file storage, 2 active projects, and projects pause after a week of inactivity. Pro starts at $25 a month and Team at $599 a month. See Supabase pricing.
• Firebase Spark (free): Firestore with 1 GiB stored, 50,000 document reads and 20,000 writes per day; Authentication free up to 50,000 monthly active users. Cloud Storage and Cloud Functions are not available on Spark and need the pay-as-you-go Blaze plan. See Firebase pricing.

The billing models behave differently as you grow. Supabase is a monthly plan plus compute and usage, so costs are fairly predictable. Firestore charges per document read, write and delete, so a screen that lists 500 documents costs 500 reads each time it loads, and a real-time listener left open can multiply that. Set a budget alert on Blaze from day one. Our guide to hosting costs for an AI-built app covers the rest of the bill.

What if I want to switch later?

It's possible, but it's a project, not a setting.

• Firebase to Supabase: documents have to be reshaped into tables, user accounts exported and imported, security rules rewritten as RLS policies, and every query in the app changed.
• Supabase to Firebase: the reverse, plus giving up SQL joins and reports.

Because Supabase is built on Postgres and is open source, your data and schema are portable to any Postgres host. Firestore data can be exported, but the app code is tied to Firebase's SDKs. If long-term independence matters to you, that counts for Supabase.

If you're weighing a switch because the current app is struggling, read rewrite or fix your AI-built app first. The backend is rarely the root problem.

How do I choose?

Answer these four questions:

1. Which tool am I building with? Go with its default unless you have a strong reason not to.
2. Is my data relational? Many linked records and reports point to Supabase.
3. Is it a mobile app that must work offline? That points to Firebase.
4. Who will maintain it? A developer comfortable with SQL will move faster on Supabase; a team already on Google Cloud may prefer Firebase.

Quick answers

Is Supabase cheaper than Firebase? It depends on usage. Supabase is easier to predict; Firestore can be very cheap at low volume and expensive with heavy reads.

Can I use Firebase Auth with a Supabase database? Supabase supports third-party auth providers, including Firebase Auth, but it adds complexity. Use one platform's auth unless you have a reason not to.

Which is more secure? Neither by default. Security depends on your RLS policies or Security Rules.

Does Supabase work for mobile apps? Yes. It has client libraries for Flutter, Swift, Kotlin and React Native.

Not sure which fits your app?

If you're deciding before you build, or wondering whether your current backend is set up safely, our Supabase security review and MVP development pages explain how we can help. You can also contact us with your situation.