Migrating from Firebase to Supabase in React Native

Why move from Firebase to Supabase, and when not to?

The honest reasons are specific: you want a relational (SQL) database instead of Firestore’s document model, you want to own your stack on open-source Postgres rather than a proprietary Google service, or Firestore’s pricing and query limits have started to bite. Supabase (the open-source repo carries over 100,000 GitHub stars) maps onto what Firebase apps already have, auth, a database, storage, realtime, except on Postgres and open source. The reframe that keeps it sane: this is a data-layer migration, not a UI rewrite; your React Native screens barely change, the client library and the data model underneath them change a lot.

When not to move: if the Firebase app works, the document model fits your data, and nothing about pricing or lock-in actually hurts, a migration is months of risk for a sideways result. “Open source is nicer in principle” is not a forcing function. The good migrations are driven by a real relational need or a real cost wall, the same honest-trigger logic as the Bubble-to-Supabase migration, and the same pricing-and-limits pressure that drives escaping FlutterFlow’s Firebase limits.

What maps to what?

The translation table is the migration plan in miniature, and the document-to-relational shift is the hard part:

Firebase	Supabase	The catch
Firestore (documents)	Postgres tables	Nested documents become normalized tables + joins
Security Rules	Row Level Security policies	Re-author per table; audit, do not transliterate
Firebase Auth	Supabase Auth	UIDs migrate; password hashes do not
Cloud Storage	Supabase Storage	Re-host files; URLs change
Cloud Functions	Edge Functions / Postgres functions	Re-platform the logic
Realtime listeners	Supabase Realtime / Postgres changes	Subscription model differs

The load-bearing row is the first: Firestore’s denormalized, nested documents have to become normalized relational tables, which is a genuine redesign, not a copy. A collection of documents with embedded arrays becomes parent and child tables with foreign keys, and getting that schema right is most of the work. The second row decides safety: Firestore Security Rules become Postgres RLS policies, and the migration is the once-ever chance to audit them rather than carry over rules that were looser than you remember.

How does the AI-assisted migration run?

Logic and schema first, screens last, the same staged order as every migration the agent does well:

1. Design the Postgres schema from the Firestore structure: the agent proposes normalized tables from your collections, and you correct the relationships it gets wrong (it will over-nest or under-normalize on first pass).
2. Export and transform the data: Firestore exports to JSON, the agent writes the transform that flattens nested documents into relational rows, and you migrate into Postgres.
3. Re-author RLS policies from the Security Rules, audited per table, with auth.uid() checks the equivalent of Firestore’s request.auth.
4. Swap the client library: replace the Firebase SDK calls with supabase-js, which is where the agent earns its keep, mechanical find-and-replace of query patterns, queries become SQL-shaped (.from().select()), listeners become Realtime subscriptions.

Auth needs its own plan: Firebase UIDs can be imported, but password hashes generally cannot move cleanly, so password users go through a reset-on-first-login flow while OAuth identities (Google, Apple) re-link by provider, the same auth ceremony as any backend migration. The data transform and the SDK-call swap are the agent’s strengths; the schema design and the RLS audit are where human judgment is non-negotiable.

What breaks, and how do you de-risk it?

Three traps. The realtime model differs: Firestore listeners and Supabase Realtime have different semantics, so screens relying on live updates need testing, not just translation, and the live chat or feed is where this surfaces. Offline behavior differs: Firestore’s offline persistence is more built-in than Supabase’s, so an app that leaned on it needs an explicit local-cache strategy. And the cutover itself, at typical app scale, is better as a planned freeze-export-import-verify window than a fragile dual-write, since reconciling two live backends is harder than the rest of the migration combined.

Verify on cutover with the same discipline as any data move: per-table row counts, spot-checked records, RLS tested adversarially (try to read another user’s row), and one full journey per role before the announcement. The screens are the easy part; a free VP0 design is the same starting point on either backend, so the agent’s effort lands on the schema, the RLS, and the SDK swap, not the UI.

Key takeaways: Firebase to Supabase

• It is a data-layer migration, not a UI rewrite: screens barely change; the client library and data model change a lot.
• The hard part is document-to-relational: Firestore’s nested documents become normalized Postgres tables with foreign keys, a real redesign.
• Security Rules become RLS policies you audit, the once-ever chance to fix rules looser than you remember.
• Auth is a planned ceremony: UIDs import, password hashes do not, so password users reset on first login; OAuth re-links by provider.
• Cut over with a freeze-and-verify window, test the realtime and offline differences, and migrate only with a real relational or cost forcing function.

Frequently asked questions

How do I migrate from Firebase to Supabase in a React Native app? Design a normalized Postgres schema from your Firestore collections, export and transform the document data into relational rows, re-author Security Rules as Row Level Security policies, and swap the Firebase SDK for supabase-js (queries become SQL-shaped, listeners become Realtime). Plan a reset-on-first-login auth flow. A free VP0 design is the same starting point on either backend.

Is Firebase to Supabase a big rewrite? Not of the UI: your React Native screens barely change. The real work is the data layer, turning Firestore’s nested documents into normalized Postgres tables, converting Security Rules to RLS, and swapping the client library. The agent handles the mechanical SDK swap; the schema and RLS need human judgment.

What happens to Firestore’s document structure in Postgres? It gets normalized: nested documents and embedded arrays become parent and child tables joined by foreign keys, rather than copied across. Getting that relational schema right is the hardest and most valuable part of the migration, and a direct document-to-row copy is usually the wrong move.

Do user passwords transfer from Firebase Auth to Supabase? UIDs can be imported but password hashes generally cannot migrate cleanly, so password users go through a reset-on-first-login flow via email, while OAuth identities like Google and Apple re-link by provider. Plan and communicate this auth ceremony as part of the cutover.

Should I migrate from Firebase to Supabase? Only with a real forcing function: you need a relational SQL model instead of documents, you want open-source Postgres ownership, or Firestore’s pricing or query limits hurt. If the Firebase app works and the document model fits, the migration is months of risk for a sideways result.