Convex vs Firebase vs Supabase for Real-Time Apps (2026)

Building a real-time app — chat, collaboration, live dashboards, multiplayer? Your database choice determines how painful (or pleasant) real-time features will be.

Convex, Firebase, and Supabase each handle real-time differently. Here's what matters.

Quick Comparison

Feature	Convex	Firebase (Firestore)	Supabase
Real-time model	Reactive queries	Document listeners	Postgres changes (CDC)
Latency	~50ms	~100-200ms	~200-500ms
Consistency	Strong (serializable)	Eventual	Strong (Postgres)
Server functions	Built-in (TypeScript)	Cloud Functions	Edge Functions (Deno)
Database type	Document-relational	Document (NoSQL)	Relational (PostgreSQL)
Offline support	Limited	Excellent	Limited
Type safety	End-to-end	Partial	Partial
Free tier	Generous	Generous	Generous
Self-host	No	No	Yes
Pricing model	Usage-based	Usage-based	Usage-based

Convex: Reactive by Default

Convex was built from the ground up for real-time. Every query is automatically reactive — when underlying data changes, all clients viewing that data update instantly.

How Real-Time Works

// This query automatically updates when any message changes
export const listMessages = query({
  args: { channelId: v.id("channels") },
  handler: async (ctx, args) => {
    return await ctx.db
      .query("messages")
      .withIndex("by_channel", (q) => q.eq("channelId", args.channelId))
      .order("desc")
      .take(50);
  },
});

// Client — automatically re-renders on changes
const messages = useQuery(api.messages.listMessages, { channelId });

No subscription setup. No listener management. No cleanup. The query just stays in sync.

Strengths

• Zero real-time boilerplate. Every query is live by default. No WebSocket management.
• Strong consistency. Serializable transactions mean no stale data, no conflict resolution needed.
• End-to-end TypeScript. Schema, server functions, and client queries are all type-safe with inference.
• Server functions as the data layer. Queries and mutations run server-side with full database access. No direct client-database connection to secure.
• Automatic optimistic updates. Mutations update the client immediately while the server confirms.

Weaknesses

• No self-hosting. Convex is cloud-only. Your data lives on their infrastructure.
• Vendor lock-in. Convex's query and mutation model is proprietary.
• Not PostgreSQL. If you need SQL, joins, or the Postgres ecosystem, Convex isn't it.
• Newer platform. Smaller community, fewer examples, less battle-tested at massive scale.
• Limited offline support. No built-in offline persistence like Firebase.

Best For

Apps where real-time is a core feature: chat, collaboration, live dashboards, multiplayer games. Teams that want the simplest real-time DX.

Firebase (Firestore): The Established Choice

Firebase has been the default real-time database for over a decade. Firestore (Firebase's current database) provides document-based real-time sync with excellent offline support.

How Real-Time Works

// Listen to a collection
const unsubscribe = onSnapshot(
  query(collection(db, "messages"), 
    where("channelId", "==", channelId),
    orderBy("createdAt", "desc"),
    limit(50)
  ),
  (snapshot) => {
    const messages = snapshot.docs.map(doc => ({
      id: doc.id,
      ...doc.data()
    }));
    setMessages(messages);
  }
);

// Clean up
return () => unsubscribe();

Strengths

• Offline-first. Best offline support of any real-time database. Reads and writes work offline, sync when connectivity returns. Essential for mobile apps.
• Massive scale. Google infrastructure. Proven at millions of concurrent connections.
• Multi-platform SDKs. Web, iOS, Android, Flutter, Unity, C++ — the broadest SDK coverage.
• Security Rules. Declarative security rules that run on Google's servers. Well-understood model.
• Real-time + REST. Use real-time where you need it, REST for everything else.

Weaknesses

• NoSQL limitations. No joins. Denormalized data means duplication and complex update patterns.
• Eventual consistency. Multi-document operations aren't strongly consistent by default. Real-time listeners may see intermediate states.
• Complex pricing. Per-read, per-write, per-delete pricing is hard to predict. Poorly structured queries can be expensive.
• No self-hosting. Google Cloud only.
• Security Rules are limited. Complex authorization logic is awkward in the declarative rules language.
• Vendor lock-in. Deep Firebase integration makes migration very difficult.

Best For

Mobile-first apps that need offline support. Apps with simple data models. Teams already in the Google ecosystem. The safest choice for scale and reliability.

Supabase: Real-Time on PostgreSQL

Supabase adds real-time capabilities to PostgreSQL through Change Data Capture (CDC). Listen to database changes and push them to connected clients.

How Real-Time Works

// Subscribe to changes
const channel = supabase
  .channel('messages')
  .on(
    'postgres_changes',
    {
      event: 'INSERT',
      schema: 'public',
      table: 'messages',
      filter: `channel_id=eq.${channelId}`,
    },
    (payload) => {
      setMessages(prev => [payload.new, ...prev]);
    }
  )
  .subscribe();

// Clean up
return () => supabase.removeChannel(channel);

Strengths

• PostgreSQL underneath. Full SQL, joins, extensions, RLS. The power of a real relational database.
• Self-hostable. Run on your own infrastructure.
• Row-Level Security. PostgreSQL RLS policies for fine-grained access control.
• Flexible real-time. Subscribe to specific tables, events (INSERT/UPDATE/DELETE), and filtered rows.
• No vendor lock-in on data. It's PostgreSQL — migrate anywhere.

Weaknesses

• Real-time is an add-on, not core. Supabase's real-time is CDC-based — you get change notifications, not reactive queries. You manage local state yourself.
• Higher latency. Postgres changes → Realtime server → client. More hops = more latency (200-500ms typical).
• State management burden. You receive change events but must maintain the client-side state yourself. More code than Convex or Firebase.
• Scaling real-time is harder. PostgreSQL's replication-based approach has limits compared to purpose-built real-time systems.
• Limited offline support. No built-in offline persistence or sync.

Best For

Apps that need real-time features on top of a relational database. Teams that value PostgreSQL's ecosystem and want to avoid NoSQL trade-offs.

Head-to-Head: Real-Time Scenarios

Chat Application

Winner: Convex. Reactive queries mean messages appear instantly for all participants. Zero boilerplate for real-time. Strong consistency prevents message ordering issues.

Firebase is a close second with proven chat infrastructure. Supabase works but requires more client-side state management.

Collaborative Document Editing

Winner: Convex for structured data collaboration. For text editing specifically, consider dedicated CRDTs (Yjs, Liveblocks) on top of any database.

Live Dashboard / Analytics

Winner: Supabase. Dashboards benefit from SQL's aggregation capabilities. Real-time CDC pushes updates to the dashboard. The slight latency increase doesn't matter for dashboards.

Mobile App with Offline Mode

Winner: Firebase. Unmatched offline support. Users can read and write data offline, everything syncs when they're back online. Essential for mobile apps in areas with spotty connectivity.

Multiplayer Game State

Winner: Convex. Strong consistency + low latency + reactive queries = clean multiplayer state management. No conflict resolution needed.

Pricing for Real-Time

Convex

• Free: 1M function calls/month
• Pro: $25/month (includes generous limits)
• Real-time is included — no extra cost per listener

Firebase (Firestore)

• Free: 50K reads/day, 20K writes/day
• Pay-as-you-go: $0.06/100K reads, $0.18/100K writes
• Each real-time listener counts as a read on every update
• Warning: Real-time listeners can generate many reads. A chat room with 100 messages and 50 listeners = 5,000 reads per message.

Supabase

• Free: 500MB database, 200 concurrent real-time connections
• Pro: $25/month (500 concurrent connections)
• Real-time connections and messages have their own limits

Firebase's per-read pricing makes real-time features expensive at scale. Convex and Supabase have more predictable real-time costs.

FAQ

Can I add real-time to an existing PostgreSQL app?

Yes — Supabase Realtime can be used standalone (without the full Supabase platform). Alternatively, look at ElectricSQL or PowerSync for PostgreSQL real-time sync.

Which has the lowest latency?

Convex (~50ms) < Firebase (~100-200ms) < Supabase (~200-500ms). For most apps, all three are fast enough. Convex's advantage matters for multiplayer games and collaborative editing.

Can I use Convex with an existing database?

No. Convex is its own database. You can sync data between Convex and other databases, but Convex is the source of truth for real-time features.

Is Firebase Realtime Database still relevant?

Firebase Realtime Database (the original) is still available and works well for simple use cases. Firestore is the recommended choice for new projects.

The Verdict

• Convex for the best real-time developer experience. If real-time is core to your app, Convex eliminates an entire category of complexity.
• Firebase for mobile-first apps with offline requirements. The proven choice at massive scale.
• Supabase for real-time features on a relational database. Best when you need SQL's power and real-time is supplementary.

For new real-time-first applications in 2026, Convex offers the most compelling DX. For adding real-time to an existing app, Supabase lets you keep PostgreSQL while gaining live updates.