A detailed comparison of Supabase and Firebase — database, authentication, real-time features, pricing, vendor lock-in, and which backend-as-a-service makes sense for different project types.
Supabase vs Firebase: which should you choose? Supabase is an open-source Firebase alternative built on PostgreSQL. Choose Supabase for: relational data, SQL queries, complex data relationships, avoiding vendor lock-in, and self-hosting capability. Choose Firebase for: real-time synchronization (especially mobile apps), tight Google Cloud integration, NoSQL document-based data, and rapid prototyping. Supabase is better for web applications and SaaS products; Firebase is better for mobile-first apps and real-time collaborative features.
Backend-as-a-service platforms promise you won't need to build a backend from scratch. That promise is mostly true — until it isn't. The trick is understanding where each platform's abstractions help you and where they trap you.
We've shipped projects on both Supabase and Firebase. We now default to Supabase for nearly everything. This guide explains why, and the specific situations where Firebase is still the better choice.
This is the most important distinction, and it affects everything else:
Supabase is built on PostgreSQL — a relational database. Your data lives in tables with rows and columns, connected by foreign keys. You query it with SQL. If you've used any relational database, Supabase will feel familiar.
Firebase is built on Firestore — a NoSQL document database. Your data lives in collections of documents, each containing key-value pairs. There are no JOINs. You query by document path and field values.
This isn't a minor implementation detail. It determines how you model your data, how you query it, what's easy, and what's painful.
| Feature | Supabase | Firebase |
|---|---|---|
| Database | PostgreSQL (relational, SQL) | Firestore (NoSQL, document) |
| Real-time | PostgreSQL changes via websockets | Native real-time sync (Firestore) |
| Authentication | Built-in (email, OAuth, magic link, phone) | Built-in (email, OAuth, phone, anonymous) |
| Storage | S3-compatible object storage | Cloud Storage for Firebase |
| Functions | Edge Functions (Deno) | Cloud Functions (Node.js, Python) |
| Hosting | No built-in hosting | Firebase Hosting (static + SSR) |
| Offline support | Limited (client-side caching) | Excellent (Firestore offline persistence) |
| Open source | Yes — self-hostable | No — Google proprietary |
| Vendor lock-in | Low — it's PostgreSQL underneath | High — proprietary APIs and data format |
| Pricing model | Usage-based (database, storage, bandwidth) | Usage-based (reads, writes, storage) |
| SQL support | Full SQL | No SQL (document queries only) |
| Data relationships | Foreign keys, JOINs, constraints | Manual denormalization, no JOINs |
Your data is relational. You define schemas, create tables, set up foreign keys, and write SQL. This means:
Your data is organized in documents and collections. No schema, no foreign keys, no JOINs. This means:
Our take: For web applications and SaaS products — where data is inherently relational (users have organizations, organizations have projects, projects have tasks) — Supabase's PostgreSQL foundation is dramatically easier to work with. Firebase's document model works well for chat messages, activity feeds, and other naturally hierarchical data.
Firebase's real-time synchronization is genuinely excellent. When a document changes in Firestore, every connected client sees the update instantly. No polling, no websocket management, no server logic. It just works.
This is why Firebase dominates in:
Supabase has real-time capabilities (PostgreSQL changes broadcast via websockets), and they work well. But Firebase's real-time sync is deeper — it handles offline persistence, conflict resolution, and optimistic updates at the SDK level. Supabase gives you the building blocks; Firebase gives you the finished product.
If real-time synchronization is your application's core feature, Firebase has a meaningful advantage.
Both platforms offer solid authentication:
Supabase's auth is built on GoTrue and integrates with PostgreSQL's Row Level Security (RLS). You write security policies in SQL directly on your tables. It's powerful but requires understanding PostgreSQL RLS syntax.
Firebase Auth integrates with Firestore security rules. The rules language is custom (not SQL) but well-documented and flexible.
In practice, both handle authentication well for most applications. Neither is a reason to choose one platform over the other.
This is where the comparison gets uncomfortable for Firebase.
Both offer generous free tiers for prototyping:
Firebase's pricing model penalizes relational access patterns. If your application frequently reads multiple related documents (which most web apps do), costs compound fast. Supabase's PostgreSQL model handles JOINs at the database level — one query, one cost, regardless of how many tables are involved.
Firebase locks you in. Your data is in Firestore's proprietary format, queried through proprietary APIs, secured with proprietary rules. Moving off Firebase means rewriting your data layer, your queries, your auth, and your security model. We've seen teams spend 3–6 months migrating off Firebase — and these were teams with relatively simple applications.
Supabase is PostgreSQL. If you outgrow Supabase or want to leave, you export your PostgreSQL database and connect it to any PostgreSQL host — AWS RDS, Google Cloud SQL, a self-managed server. Your data, your schema, your queries all transfer. You rewrite the Supabase-specific parts (auth, real-time, storage), but the core — your database — moves cleanly.
Supabase can also be self-hosted. The entire platform is open source. You can run it on your own infrastructure if you need to — for compliance, cost, or control reasons. Firebase offers no self-hosting option.
For any project with a lifespan beyond 2–3 years, vendor lock-in should be a primary consideration. Businesses change, requirements evolve, and platforms alter their pricing. PostgreSQL has existed for 30+ years. Firestore has existed for 7.
Supabase Edge Functions run on Deno at the edge (close to users). They're fast to cold-start, TypeScript-native, and suitable for lightweight API endpoints, webhooks, and data transformations.
Firebase Cloud Functions run on Google Cloud's infrastructure. They support Node.js and Python, have access to the full Google Cloud ecosystem, and handle more complex workloads (background jobs, scheduled tasks, heavy computation).
Firebase's Cloud Functions are more mature and more capable for complex backend logic. Supabase's Edge Functions are lighter, faster to deploy, and better for simple API endpoints. For heavy backend work, both platforms eventually push you toward building a separate backend service.
Default to Supabase for web applications, SaaS products, and anything with relational data. The PostgreSQL foundation, lower lock-in, better pricing at scale, and growing ecosystem make it the safer long-term choice.
Choose Firebase when real-time synchronization is a core feature, when you're building primarily for mobile, or when you're prototyping within the Google Cloud ecosystem and speed-to-demo matters more than long-term architecture.
Don't underestimate the migration cost. We've helped teams move off Firebase when they hit scaling pain or cost surprises. It's doable, but it's not fun. If there's any chance you'll need relational queries, complex reporting, or predictable costs at scale — start with Supabase.
For a deeper comparison of the databases themselves, see our guide on PostgreSQL vs MySQL — it covers PostgreSQL's strengths in more detail. And for how PostgreSQL fits into our broader architecture, see our API development services and technology stack.
Building a project and need help choosing the right backend platform? Get started with a conversation — we'll look at your data model, real-time needs, and scaling requirements and recommend the architecture that fits. No platform loyalty, just honest advice.
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