Firebase vs. Supabase in 2026: Choosing a Backend for Your App
Backend-as-a-Service (BaaS) platforms promise one simple thing: you don't have to build your own backend. Database, authentication, file storage and realtime sync come ready-made — you just wire them into your app. Two names dominate the space today: Google's Firebase and the open-source challenger Supabase.
We use both platforms on real projects, so this won't be a battle of marketing pages. Let's look at how they differ architecturally, what that means in practice, and — just as importantly — when neither one makes sense.
The fundamental difference: NoSQL vs. Postgres
The biggest difference isn't the logo or the pricing — it's the data model.
Firebase is built on Firestore, a document-oriented NoSQL database (or the older Realtime Database). You store data as documents in collections, with no schema and no relations. For simple structures it's convenient — until you need to join data. Firestore has no JOINs, aggregations are limited, and complex queries are solved by denormalization: duplicating the same data in multiple places and keeping it in sync on every write. That's extra work and a source of bugs that grows with your app's complexity.
Supabase is, at its core, full-blown PostgreSQL. Relations, JOINs, transactions, views, full-text search, SQL functions — everything you expect from a relational database. If your data has structure (and most business apps' data does: customers, orders, bookings, invoices), the relational model is more natural and cheaper to maintain over time.
In practice: building an e-shop, booking system or CRM on Firestore means fighting your data model from day one. The same apps on Postgres are routine.
Side-by-side comparison
| Area | Firebase | Supabase |
|---|---|---|
| Database | Firestore (NoSQL, documents) | PostgreSQL (relational, SQL) |
| Queries | Limited, no JOINs | Full SQL, views, functions |
| Auth | Firebase Auth (very mature) | GoTrue (e-mail, OAuth, magic links) |
| Realtime | Native, excellent | Postgres replication, good |
| Storage | Cloud Storage (GCS) | Storage on S3-compatible backends |
| Server functions | Cloud Functions (Node, Python…) | Edge Functions (Deno/TypeScript) |
| Vendor lock-in | High | Low (open source, standard Postgres) |
| Self-hosting | No | Yes (Docker, your own infrastructure) |
| Local development | Emulator Suite | Supabase CLI (full local stack) |
| Pricing model | Pay-per-use (operations, transfer) | Fixed tiers + usage |
Authentication
Firebase Auth is the most mature part of the whole platform — phone verification, anonymous accounts, dozens of providers, security rules integrated with Firestore. If auth is the main thing you want from a BaaS, Firebase is the safe bet.
Supabase Auth (GoTrue) covers the standard scenarios: e-mail and password, magic links, OAuth via Google, Apple, GitHub and more. The big advantage: users are ordinary rows in a Postgres table, so you can join them with your own data and control access via Row Level Security directly in SQL. It's a more consistent model than the combination of Firebase Auth plus security rules written in a separate language.
Realtime
Firebase was built around realtime sync and it shows — offline support in the mobile SDKs, automatic synchronization on reconnect, conflict scenarios solved for you. For chat apps, collaborative tools or live dashboards, this is the strongest argument for Firebase.
Supabase realtime works on top of Postgres logical replication: you subscribe to table changes (INSERT/UPDATE/DELETE) over websockets. For most use cases (refreshing a bookings list, notifying about a new order) it's plenty. But it doesn't solve offline-first synchronization for you — that part you build yourself.
Pricing: beware of pay-per-use
Firebase charges per operation: every document read, write and delete counts. The free tier is generous and small apps run for free. The problem comes with growth — an inefficient data model (and Firestore's denormalization pushes you toward one) means multiplied reads, and the bill can be an unpleasant surprise. Estimating costs upfront is genuinely hard.
Supabase has a more predictable model: a fixed monthly tier (free, ~USD 25 Pro) plus overage fees for storage and transfer. For business planning, a fixed number is an advantage. And if costs outgrow reason, there's an escape hatch: self-hosting.
Vendor lock-in and your exit strategy
This is where the difference is sharpest.
Firebase is a one-way street. Firestore has no standard protocol, security rules are proprietary, Cloud Functions are tied to Google Cloud. Migrating away means rewriting your data layer, auth and server logic — easily months of work for a larger app.
Supabase is standard Postgres. One pg_dump and you have your complete data and schema. The whole platform is open source and can run on your own server via Docker. Even if Supabase disappeared tomorrow, your app keeps running — you just host Postgres and auth elsewhere. For companies thinking in years, that's a fundamental insurance policy.
When to choose which
Firebase makes sense when:
- you're building a mobile app with an offline-first, realtime-sync core,
- your auth scenarios are complex (phone verification, anonymous accounts upgraded later),
- your data is simple and the document model genuinely fits,
- you're in the Google ecosystem (Analytics, Crashlytics, Cloud Messaging in one place).
Supabase makes sense when:
- your data is relational — orders, bookings, inventory, invoicing,
- you want SQL, reporting and analytical queries without exports,
- vendor lock-in is a risk you care about (or compliance requires data on your own infrastructure),
- your team knows SQL — the learning curve is then minimal.
When neither: a custom backend
BaaS platforms have a ceiling. You hit it when your app needs:
- complex server-side business logic — price calculations, approval workflows, integrations with accounting, payment gateways or ERP; serverless functions can do it, but at dozens of functions they become a backend chopped into hard-to-maintain pieces,
- performance guarantees — you don't tune a BaaS, you just use it; when a query is slow, your options are limited,
- specific data requirements — audit trails, record versioning, complex cross-module reporting.
In that situation, an API-first custom backend is cheaper in the long run than bending a BaaS. We build custom backends designed to grow with the app — and happily hybrid: Postgres as the foundation, BaaS pieces (auth, storage) where they save time.
Our take from practice
For most new projects these days, we reach for Supabase or straight for a custom Postgres backend. The reason is prosaic: the business apps we build — booking systems, custom CRMs, internal company tools — are inherently relational. We choose Firebase deliberately where its realtime and offline sync win, typically in mobile apps with unstable connectivity.
And an important closing note: choosing a BaaS is not a forever decision. A sensibly built app keeps its data layer separated so it can be swapped. That's exactly how we approach it — start fast and cheap, but don't cement yourself in.
Not sure what's right for your project?
Choosing a backend is a decision for years — and the wrong one is expensive to rewrite. It's closely tied to choosing the technology for your whole app and the serverless question.
If you're unsure, book a consultation — we'll go through your project and recommend a stack regardless of fashion waves. And if you want to know what your app would cost right away, the configurator gives you an estimate in two minutes.
