Backend-as-a-Service (BaaS) platforms give frontend developers a complete backend without managing servers — database, authentication, file storage, real-time subscriptions, and serverless functions in one platform. In 2026, the BaaS market has matured beyond Firebase into a rich ecosystem of open source and managed options. This comparison helps frontend developers pick the right backend.
Quick Comparison
| Feature | Supabase | Appwrite | Convex | Firebase |
|---|---|---|---|---|
| Database | PostgreSQL (full SQL) | MariaDB (SQL) + NoSQL | Custom (reactive, ACID) | Firestore (NoSQL) + Realtime DB |
| Authentication | Built-in (50+ providers, Row Level Security) | Built-in (30+ providers, RBAC) | Built-in (via auth providers) | Built-in (Google, email, anonymous) |
| Real-Time | Yes (PostgreSQL replication) | Yes (realtime API) | Yes (automatic, core feature) | Yes (Firestore realtime listeners) |
| File Storage | Yes (S3-compatible) | Yes (built-in) | Yes (file storage) | Yes (Cloud Storage) |
| Serverless Functions | Edge Functions (Deno) | Functions (Node.js, Python, Deno, etc.) | Functions (TypeScript — built into the platform) | Cloud Functions (Node.js, Python) |
| Open Source | Yes (Apache 2.0) | Yes (BSD-3) | No (proprietary) | No (Google proprietary) |
| Self-Hosted | Yes (Docker, K8s) | Yes (Docker, 1-click DO) | No | No (emulator only for dev) |
| Generous Free Tier | Yes (50K MAU, 500MB DB, 1GB storage) | Yes (75K MAU, 2GB DB, 5GB storage) | Yes (1M rows, 1GB storage) | Yes (50K MAU, 1GB Firestore, 10GB storage) |
| Pricing Start | $25/mo Pro | $15/mo Pro | $25/mo Pro | $25/mo (Blaze — PAYG) |
When to Choose Each Platform
Supabase — Best for: Most projects. PostgreSQL is the killer feature — you get a real database with SQL, joins, migrations, and the entire Postgres extension ecosystem (PostGIS, pgvector, full-text search). Row Level Security (RLS) is a genuinely innovative approach to authorization. Weak spot: Real-time subscriptions are built on PostgreSQL replication (not WebSocket-first); complex real-time apps may feel less responsive than Firebase or Convex.
Appwrite — Best for: Teams that want the Firebase experience with open source and self-hosting. Appwrite is the most Firebase-like open source alternative — it abstracts database details (function-first, not SQL-first), which some frontend developers prefer. Weak spot: Less mature than Supabase; smaller community; MariaDB is less powerful than PostgreSQL for complex queries.
Convex — Best for: Real-time-first applications where every user interaction needs instant reactivity. Convex's reactive database is unique — queries automatically re-run when data changes, eliminating the need for manual cache invalidation or subscription management. Weak spot: Proprietary; smaller ecosystem; locked into Convex's runtime; not self-hostable.
Firebase — Best for: Teams already in the Google Cloud ecosystem, or projects that value the most mature, battle-tested BaaS. Firebase has been around the longest and has the deepest integration with Google Analytics, Crashlytics, and the GCP ecosystem. Weak spot: No SQL database (Firestore is NoSQL with limited querying); vendor lock-in; not open source.
Decision Matrix
| Scenario | Best BaaS | Why |
|---|---|---|
| Most projects, want SQL + open source | Supabase | PostgreSQL, RLS, best open source story |
| Firebase-style but open source + self-hosted | Appwrite | Most Firebase-like, generous free tier |
| Real-time-first app (chat, collaboration) | Convex | Best reactive model, automatic cache invalidation |
| Google ecosystem, want most mature platform | Firebase | Most mature, deepest Google integration |
| Self-hosted, full control, SQL essential | Supabase (self-hosted) | Apache 2.0, Docker deploy, full Postgres |
Bottom line: Supabase is the best BaaS for 80% of projects — PostgreSQL alone makes it worth choosing (you can always migrate to your own Postgres later), the free tier is generous, and the open source model means no lock-in. Convex is the pick for real-time-first applications. Firebase is still solid but the NoSQL-only approach and vendor lock-in are real concerns in 2026. See also: Supabase vs Firebase vs Neon and Best Open Source SaaS Alternatives.