Firebase → Supabase
What it saves, what actually moves, what you rebuild — and the thing that catches people.
What it costs, and what it saves
Firebase Blaze bills per operation — about $0.06 per 100,000 reads — so a read-heavy app can produce a surprising invoice. Supabase Pro is a flat $25/month, or free self-hosted. The saving is unpredictability as much as amount.
Moves cleanly
User accounts, with password hashes — Supabase can import Firebase Auth users including bcrypt/scrypt hashes, which is the part everyone assumes is impossible.
You rebuild
Every Firestore query, every security rule, and any Cloud Function. Document queries become SQL.
What Firebase costs you today
The Spark tier is free with hard quotas. Beyond it, Blaze is pay-as-you-go and metered on operations rather than seats: roughly $0.06 per 100,000 document reads, $0.18 per 100,000 writes and $0.02 per 100,000 deletes on Firestore, with Realtime Database around $5 per GB stored and $1 per GB downloaded. A modest app at 5,000 daily users lands near $12 a month. The number that surprises people is not the rate, it is the shape — a badly written listener that re-reads a collection on every render costs the same as a feature nobody asked for. Figures checked 2026-07-31.
What actually holds you in
High, and it is the query layer rather than the data. Exporting documents from Firestore is straightforward; rewriting every query, security rule and Cloud Function that assumed a document store is not. Firebase Authentication is the sharper hook — user records and password hashes are exportable, but any app depending on Firebase's client SDKs for session handling needs its auth flow rebuilt, not repointed. Teams that keep business logic out of Cloud Functions and behind their own API keep the exit affordable.
What you are moving to
Supabase wraps a real Postgres database in the things that made Firebase pleasant: instant REST and GraphQL APIs, row-level security, authentication, file storage, realtime subscriptions and edge functions. The difference that matters is underneath. Your data is in Postgres, so you get SQL, joins, transactions, extensions like PostGIS and pgvector, and the ability to pick up the database and run it on any host on earth. It is Apache-2.0 and self-hostable with Docker Compose, and the hosted tier exists for people who would rather not. Around 107k GitHub stars and pushed to daily.
Free tier for small projects; hosted Pro from about $25/month. Fully self-hostable at no licence cost.
Supabase strengths
- Real Postgres — SQL, joins, transactions and the whole extension ecosystem
- Genuinely portable: the database runs anywhere, hosted or not
- Apache-2.0 with a complete self-host path, not a crippled community edition
- pgvector built in, so AI features do not need a second database
What you give up
- You now have a Postgres database to think about — indexes, connections, vacuum
- Mobile offline sync is weaker than Firebase's SDKs
- Self-hosting the full stack is more moving parts than the hosted product suggests
- Younger than Firebase; some edges are still being filed off
The migration, step by step
- 1Export Firestore collections to JSON with the Firebase CLI
- 2Design the Postgres schema — resist a one-to-one document dump into JSONB, which throws away the reason to move
- 3Import users first and verify a real login works before touching data
- 4Rewrite security rules as row-level security policies; this is the conceptual jump
- 5Port Cloud Functions to Edge Functions, then dual-run before cutting over
The gotcha
Firestore's offline-first client sync has no Supabase equivalent. A mobile app that depends on working offline and reconciling later will need that behaviour rebuilt by hand, and it is not a small job.
When to stay on Firebase
You are mobile-first and rely on offline sync, or your bill is small enough that the migration costs more than it saves.
Other ways off Firebase
More Layer 3 migrations
Figures verified 2026-07-31 against vendor pricing pages. Prices change and migrations differ by estate — treat the cost delta as a starting model, not a quote. Rankings and recommendations here are merit-only; affiliate income never changes a verdict. See our methodology.