Supabase and Firebase solve the same problem — a backend (database, auth, storage, APIs) without running servers — but they make opposite bets. Firebase is the mature, proprietary, NoSQL incumbent; Supabase is the open-source, SQL challenger. The right choice comes down to your data and your appetite for lock-in.
Head to head
| Supabase | Firebase | |
|---|---|---|
| Database | PostgreSQL (SQL, relational) | Firestore (NoSQL, documents) |
| Open source | Yes — self-hostable | No — proprietary (Google) |
| Lock-in | Low (standard Postgres) | Higher (Google ecosystem) |
| Realtime | Yes (Postgres changes) | Yes — a core strength |
| Auth | Built-in, row-level security | Built-in, mature, great mobile SDKs |
| Best for | Relational data, SQL teams | Mobile, flexible data, Google stack |
Choose Supabase if…
- Your data is relational and you want real SQL and joins.
- You value open source and the option to self-host (no lock-in).
- You like enforcing access at the database with Row Level Security.
Choose Firebase if…
- You're building mobile-first and want best-in-class SDKs.
- Your data is document-shaped and you want real-time sync out of the box.
- You're already in Google Cloud and want tight integration.
Pricing & the security footgun
Both have free tiers and usage-based pricing (see Supabase pricing). And both share one trap: they let the client talk to the database directly, so your rules are the only thing protecting data. On Supabase that's RLS; on Firebase it's Security Rules. Ship either with those misconfigured and your data is public — the single most common cause of leaked backends. A free Nurbak scan confirms your rules are actually protecting you before launch.