Convex vs Firebase vs Supabase Realtime (2026)

Three backends for apps that need live data. Convex: reactive queries with TypeScript. Firebase: Google's real-time database. Supabase: PostgreSQL with real-time subscriptions. Here's how to choose.

Quick Comparison

Feature	Convex	Firebase	Supabase
Database	Document (custom engine)	Document (NoSQL)	PostgreSQL (relational)
Real-time model	Reactive queries	Listener-based	PostgreSQL CDC
TypeScript	Native, end-to-end	SDK typed	SDK typed
Server functions	✅ Built-in	Cloud Functions	Edge Functions
Auth	✅ Built-in	✅ Built-in	✅ Built-in
File storage	✅ Built-in	✅ Built-in	✅ Built-in
SQL	❌ (custom query)	❌ (NoSQL)	✅ Full SQL
Self-hostable	❌	❌	✅
Free tier	Generous	Generous	Generous
Pricing model	Usage-based	Usage-based	Plan-based

Convex: Reactive Everything

How Real-Time Works

Convex queries are automatically reactive. Subscribe to a query → get updates whenever the underlying data changes.

// convex/tasks.ts (server)
import { query, mutation } from './_generated/server';

export const list = query({
  handler: async (ctx) => {
    return await ctx.db.query('tasks').order('desc').collect();
  },
});

export const create = mutation({
  args: { text: v.string() },
  handler: async (ctx, args) => {
    await ctx.db.insert('tasks', { text: args.text, done: false });
  },
});

// React component (client)
import { useQuery, useMutation } from 'convex/react';
import { api } from '../convex/_generated/api';

function TaskList() {
  const tasks = useQuery(api.tasks.list); // Auto-updates when data changes
  const createTask = useMutation(api.tasks.create);

  return (
    <div>
      {tasks?.map(task => <div key={task._id}>{task.text}</div>)}
      <button onClick={() => createTask({ text: 'New task' })}>Add</button>
    </div>
  );
}

No manual subscriptions. No WebSocket management. No cache invalidation. When any mutation changes data that a query depends on, the query re-runs and the UI updates automatically.

Strengths

True reactivity. Every query is a live query. Change data anywhere → all clients see the update instantly. No "subscribe to this specific path" — the entire query result stays fresh.

End-to-end TypeScript. Server functions, database queries, and client calls are all typed. Change a server function's return type → TypeScript errors in the client immediately.

Transactions built-in. Mutations are transactional by default. No race conditions, no partial updates.

Server functions are first-class. No separate backend needed. Queries, mutations, actions, and scheduled jobs — all defined alongside your schema.

Weaknesses

• Not SQL. Custom query API, not PostgreSQL. If you need SQL, joins, or complex relational queries: Convex isn't the fit.
• Vendor lock-in. Not self-hostable. Your data lives on Convex's infrastructure. No standard database format for migration.
• Newer platform. Less battle-tested than Firebase (10+ years) or Supabase.
• Learning curve. The reactive model is different from traditional request-response. Takes adjustment.

Best For

Collaborative apps, real-time dashboards, chat, multiplayer games. Any app where multiple users see the same data and need instant updates.

Firebase: Google's Real-Time

How Real-Time Works

Firebase Realtime Database and Firestore provide listener-based real-time:

// Firestore real-time listener
import { onSnapshot, collection, query, orderBy } from 'firebase/firestore';

const q = query(collection(db, 'tasks'), orderBy('createdAt', 'desc'));
onSnapshot(q, (snapshot) => {
  const tasks = snapshot.docs.map(doc => ({ id: doc.id, ...doc.data() }));
  setTasks(tasks);
});

Strengths

Google scale and reliability. Firebase handles millions of concurrent connections. Google's infrastructure. The most battle-tested real-time platform.

Full platform. Auth, database, storage, hosting, analytics, crashlytics, messaging, remote config — everything for mobile and web apps.

Mobile-first. Best SDKs for iOS and Android. Offline support with automatic sync. The default for mobile app backends.

Generous free tier. Spark plan: 1GB storage, 10GB bandwidth, 50K reads/day, 20K writes/day.

Weaknesses

• NoSQL limitations. No SQL. No joins. Denormalized data model requires careful planning. Complex queries are limited.
• Vendor lock-in. Deeply tied to Google Cloud. Migration is painful.
• Pricing surprises. Pay per read/write operation. Poorly designed queries or data models can create unexpectedly high bills.
• Firestore query limitations. No OR queries across fields, no full-text search, limited aggregation.
• Not TypeScript-first. SDKs are typed but the platform wasn't designed around TypeScript.

Best For

Mobile apps (iOS/Android). Apps needing the full Firebase platform. Projects that need Google's scale.

Supabase: PostgreSQL Real-Time

How Real-Time Works

Supabase uses PostgreSQL's Change Data Capture (CDC) to broadcast changes:

// Subscribe to changes
const channel = supabase
  .channel('tasks')
  .on('postgres_changes', {
    event: '*',
    schema: 'public',
    table: 'tasks',
  }, (payload) => {
    console.log('Change:', payload);
    // Update local state
  })
  .subscribe();

Strengths

Full PostgreSQL. SQL, joins, views, stored procedures, extensions (pgvector, PostGIS). The full power of PostgreSQL with real-time on top.

Open source and self-hostable. Run Supabase on your own infrastructure. No vendor lock-in for the database layer.

Row Level Security. PostgreSQL RLS policies control who can read/write what. Security at the database level, not the application level.

Full backend platform. Auth, storage, edge functions, and real-time — similar to Firebase but built on PostgreSQL.

Weaknesses

• Real-time is less elegant. CDC-based subscriptions are more manual than Convex's reactive queries. You subscribe to table changes, not query results.
• Not truly reactive. Supabase real-time tells you a row changed. You still need to update your local query/cache. Convex automatically re-runs the entire query.
• Latency. PostgreSQL CDC adds slight latency compared to purpose-built real-time databases. Fine for most apps, noticeable in gaming or high-frequency updates.
• Scaling real-time. Supabase real-time has connection limits that require awareness at scale.

Best For

Apps that need relational data AND real-time. Projects wanting PostgreSQL's power. Teams that value open source and self-hosting option.

Decision Matrix

If You Need...	Choose
Best real-time DX	Convex
SQL / relational data	Supabase
Mobile-first	Firebase
Full TypeScript	Convex
Self-hosting	Supabase
Google ecosystem	Firebase
Collaborative apps	Convex
Complex queries	Supabase
Largest ecosystem	Firebase
Open source	Supabase

Pricing

	Convex	Firebase	Supabase
Free	1M fn calls/mo	50K reads/day	500MB, 50K requests
Starter	$25/mo	Pay-as-you-go	$25/mo
Scale	Usage-based	Usage-based	$599/mo

FAQ

Which is best for a chat app?

Convex (best real-time DX) or Firebase (most battle-tested for chat). Supabase works but requires more manual real-time management.

Can I use Supabase real-time for a game?

Simple games (turn-based, leaderboards): yes. Fast-paced real-time games (multiplayer action): Convex or a dedicated game server is better.

Is Firebase still relevant in 2026?

Yes. Massive install base, Google backing, and the best mobile SDKs. But for new web projects, Convex and Supabase offer better developer experience.

Can I migrate between them?

Firebase → Supabase: Moderate effort (restructure NoSQL to SQL). Convex → Supabase: Moderate effort (different data model). Any → Firebase: Easy for simple data, complex for relational data.

Bottom Line

Convex for the best real-time developer experience. Reactive queries that "just work." Best for collaborative web apps.

Firebase for mobile apps and Google ecosystem projects. Most battle-tested. Best mobile SDKs.

Supabase for relational data with real-time capabilities. PostgreSQL power. Open source. Best when you need SQL and real-time.