Supabase vs Firebase vs Convex: The Definitive Comparison (2026)

Three backends, three philosophies. Supabase bets on PostgreSQL. Firebase bets on Google's ecosystem. Convex bets on TypeScript-native reactivity. Here's the definitive breakdown.

Architecture Overview

Supabase: PostgreSQL + REST/GraphQL API + Auth + Storage + Edge Functions + Real-time. Open-source. You're building on top of the most trusted database in the world.

Firebase: NoSQL (Firestore) + Auth + Storage + Cloud Functions + Hosting + Analytics. Google-backed. Designed for mobile-first and rapid prototyping.

Convex: TypeScript-native reactive database + Server functions + Auth + File storage + Scheduling. Full-stack TypeScript with automatic real-time.

Quick Comparison

Feature	Supabase	Firebase	Convex
Database	PostgreSQL (relational)	Firestore (document/NoSQL)	Convex (document + relational)
Query language	SQL	Firestore SDK methods	TypeScript functions
Real-time	Postgres changes (subscribe)	Built-in (native)	Built-in (native, automatic)
Auth	GoTrue (email, OAuth, SSO)	Firebase Auth (comprehensive)	Clerk/Auth0 integration
Server functions	Edge Functions (Deno)	Cloud Functions (Node.js)	Server functions (TypeScript)
File storage	S3-compatible	Cloud Storage	Built-in file storage
Offline support	Limited	Excellent (Firestore cache)	Coming soon
Open-source	Yes (Apache 2.0)	No	Partially (MIT client)
Self-host	Yes (Docker)	No	No (cloud only)
Free tier	2 projects, 500MB DB	Spark plan (generous)	1M function calls/mo
Pricing model	Per-resource	Pay-per-use	Pay-per-use

Database: The Core Difference

Supabase (PostgreSQL)

-- Full SQL power
SELECT users.name, COUNT(orders.id) as order_count
FROM users
LEFT JOIN orders ON users.id = orders.user_id
WHERE orders.created_at > NOW() - INTERVAL '30 days'
GROUP BY users.name
HAVING COUNT(orders.id) > 5
ORDER BY order_count DESC;

Advantages: JOINs, transactions, constraints, indexes, views, stored procedures, extensions (pgvector, PostGIS), and decades of tooling. Your data model is as powerful as PostgreSQL itself.

Trade-off: Schema migrations needed. More upfront design. SQL knowledge required.

Firebase (Firestore)

// Document-based queries
const snapshot = await db.collection('users')
  .where('orderCount', '>', 5)
  .where('lastOrder', '>', thirtyDaysAgo)
  .orderBy('orderCount', 'desc')
  .get();

Advantages: No schema required. Nested documents. Fast reads. Excellent offline support with local cache. Scales automatically.

Trade-off: No JOINs (denormalize everything). Limited query capabilities. Data duplication is the norm. Complex aggregations require Cloud Functions.

Convex (TypeScript-native)

// TypeScript functions with full type safety
export const getActiveUsers = query({
  handler: async (ctx) => {
    const users = await ctx.db
      .query("users")
      .filter((q) => q.gt(q.field("orderCount"), 5))
      .order("desc")
      .collect();
    return users;
  },
});

Advantages: Full TypeScript type safety end-to-end. Relations via IDs with helper functions. ACID transactions. Automatic indexes. Real-time by default — every query is live.

Trade-off: Cloud-only (no self-hosting). Newer, smaller ecosystem. Query API less powerful than raw SQL.

Real-Time: Where They Diverge Most

Supabase Real-Time

Subscribe to PostgreSQL changes via WebSocket. You explicitly subscribe to specific tables/rows.

const channel = supabase
  .channel('messages')
  .on('postgres_changes', { event: 'INSERT', schema: 'public', table: 'messages' }, 
    (payload) => console.log(payload))
  .subscribe();

Caveat: Real-time is an add-on to PostgreSQL, not native. Works well but requires explicit subscription management.

Firebase Real-Time

Firestore's real-time listeners are a core feature. Every query can be real-time.

onSnapshot(collection(db, 'messages'), (snapshot) => {
  snapshot.docChanges().forEach((change) => {
    console.log(change.type, change.doc.data());
  });
});

Strength: Real-time + offline. Firestore syncs automatically when connectivity returns.

Convex Real-Time

Every Convex query is automatically real-time. No subscription management.

// This automatically re-renders when data changes
const messages = useQuery(api.messages.list);

Winner: Convex for developer experience (zero real-time boilerplate). Firebase for offline + real-time. Supabase for real-time on top of SQL.

Auth Comparison

Supabase Auth: Email/password, magic links, phone, 30+ OAuth providers, SSO (SAML). Built-in, well-integrated, free.

Firebase Auth: Email/password, phone, 20+ OAuth providers, anonymous auth, multi-factor. The most battle-tested at scale.

Convex Auth: Integrates with Clerk, Auth0, or custom. Not built-in — you bring your own auth provider. More flexible but extra cost/setup.

Winner: Firebase for breadth and battle-testing. Supabase for built-in + self-hostable.

Server-Side Logic

Supabase Edge Functions: Deno-based, deployed globally. Good for webhooks and API endpoints. Separate deployment step.

Firebase Cloud Functions: Node.js (or Python), triggered by Firestore events, HTTP, or pub/sub. Mature but cold starts are painful.

Convex Server Functions: TypeScript functions that run alongside your database. ACID transactions with database access. No cold starts. Automatic retry.

Winner: Convex for database-centric server logic (mutations + queries are one thing). Firebase for event-driven architecture. Supabase Edge Functions for edge deployment.

Pricing Comparison

Monthly cost for a growing SaaS (10K MAU, 5GB data)

Resource	Supabase	Firebase	Convex
Database	$25/mo (Pro)	~$18/mo (Firestore reads/writes)	Included
Auth	Included	Free	Clerk ~$25/mo
Functions	Included (limited)	~$10/mo	Included
Storage	Included (100GB)	~$5/mo	Included
Bandwidth	Included (250GB)	~$12/mo	Included
Total	~$25/mo	~$45/mo	~$50/mo (with Clerk)

All three are affordable at small scale. Firebase's pay-per-use can surprise you at scale. Supabase's fixed pricing is most predictable.

When to Choose Each

Choose Supabase When:

You want PostgreSQL's power (JOINs, extensions, raw SQL)
You need to self-host or own your data
Your team knows SQL
You want the strongest open-source option
You need vector search (pgvector for AI apps)

Choose Firebase When:

You're building mobile-first (best iOS/Android SDKs)
Offline support is critical
You want Google Cloud integration
Rapid prototyping speed matters most
You need Firebase's analytics and crash reporting

Choose Convex When:

You're building a real-time collaborative app
Full-stack TypeScript type safety is a priority
You want zero-configuration real-time
ACID transactions with server functions matter
You prefer managed infrastructure (zero ops)

Migration Considerations

Firebase → Supabase

Supabase provides a Firebase migration guide. Main challenges: restructuring denormalized Firestore data into relational PostgreSQL tables. Real-time subscriptions need rewriting.

Firebase → Convex

Similar data restructuring challenges. Convex's TypeScript functions replace Cloud Functions naturally.

Supabase → Convex

PostgreSQL data exports to Convex's document model. SQL queries need rewriting as TypeScript query functions.

Difficulty ranking: Firebase → Supabase (hardest, data restructuring) > Supabase → Convex > Firebase → Convex.

FAQ

Which is best for a startup MVP?

All three work. Supabase if you know SQL. Firebase if you want the fastest prototype. Convex if you're building something real-time.

Can I use these with Next.js?

Yes, all three have excellent Next.js integration. Convex's is the tightest (automatic type inference in components).

Which scales best?

Firebase scales automatically to massive scale (Google infrastructure). Supabase scales well but requires plan upgrades. Convex handles significant scale but is the newest.

Which has the best free tier?

Supabase: 2 projects, 500MB DB, 1GB storage. Firebase Spark: generous per-day limits. Convex: 1M function calls/month. All are sufficient for side projects and early MVPs.

The Verdict

Supabase is the safe, powerful default. PostgreSQL is the right database for most apps. Open-source means no lock-in.
Firebase is best for mobile apps and rapid prototyping, especially if you're already in Google Cloud.
Convex is the future for real-time TypeScript apps, but the smallest ecosystem.

For most web apps starting in 2026, Supabase offers the best balance of power, flexibility, and community. Choose Firebase for mobile. Choose Convex if real-time TypeScript is your north star.