Supabase vs Firebase: login and a database
Supabase is our pick for most new apps, especially ones built with AI tools: you get a real Postgres database with auth, storage, realtime and edge functions, APIs generated from your tables, and an open-source stack you are not locked into. Firebase remains a strong choice for mobile and web apps that want Google to run everything, with Firestore, the Realtime Database, auth and hosting in one console. Price won't decide it, since small projects run free on either: tables and SQL point to Supabase, documents to Firebase.
Which one to pick
Your data fits tables with relations, you want SQL and row-level security to control who reads each row, or you value an open-source backend you could move later.
You are shipping a mobile or web app and want Google to host the frontend, data and functions together, with a document database and the free Spark plan to launch.
Side by side
Questions
Are Supabase and Firebase free?
Small projects run free on either. Firebase calls its free tier the Spark plan, and it lets you build and launch small apps at no cost. We do not quote paid prices because they depend on usage, so check each pricing page once real traffic arrives.
Which database model should I choose?
Supabase runs Postgres, so you work with tables, relations and SQL. Firebase offers Firestore and the Realtime Database, which store data as documents. If your app has users, orders and products that reference each other, tables usually make queries simpler.
How do they handle security?
Supabase uses Postgres row-level security, rules in the database that decide who can read or change each row. Firebase protects data with its own security rules on Firestore and the Realtime Database. Either way, write and test these rules before launch, because the default for a new project is rarely what you want in production.
Can I leave later if I outgrow it?
Supabase is open source and built on Postgres, so you can export your database or self-host the stack. Firebase is a Google service, and moving off means rewriting the parts that depend on its databases and functions. If lock-in worries you, that difference matters more than any feature.
Which works better with AI app builders?
Supabase is the backend many AI app builders connect to: Bolt, for example, links to it natively. Firebase is built into Google's own tooling and works well if you already use it. For a prototype from an AI builder, Supabase is usually the shorter path to user accounts and stored data.