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Convex vs Supabase vs Firebase for SaaS Starters 2026

·StarterPick Team
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Choosing a real-time backend for a SaaS starter is one of the earliest and hardest-to-reverse decisions you make. Convex, Supabase, and Firebase each solve the same problem — give your application a backend with auth, database, and real-time data — but their architectures, pricing models, and developer experiences are fundamentally different. This guide breaks down all three as of 2026 so you can pick the right backend for your SaaS starter without learning the hard way.

The Three Philosophies

Convex is a TypeScript-native reactive backend. You write server functions in TypeScript, and any data change automatically propagates to all subscribed clients in real time. There is no SQL. There is no REST layer to define. Your database schema is your TypeScript types.

Supabase is PostgreSQL with a developer experience layer. It gives you a managed Postgres database, Row Level Security for access control, a realtime engine that listens to Postgres WAL changes, built-in auth, and an S3-compatible storage layer. Everything is built on proven open-source infrastructure.

Firebase is Google's mature backend-as-a-service platform. Firestore (the document database) and the Realtime Database are the core offerings, with Firebase Auth, Cloud Storage, and Cloud Functions completing the platform. Firebase is the most established of the three, with the broadest mobile SDK support and the deepest Google ecosystem integration.

Architecture Deep Dive

Convex Architecture

Convex runs your backend logic in a serverless TypeScript runtime. You write "mutations" (writes), "queries" (reads), and "actions" (side effects that can call external APIs). Queries are reactive by default — when the underlying data changes, every component subscribed to that query receives the update automatically without any manual subscription management.

// convex/messages.ts
import { query, mutation } from "./_generated/server"
import { v } from "convex/values"

export const list = query({
  args: {},
  handler: async (ctx) => {
    return await ctx.db.query("messages").order("desc").take(100)
  },
})

export const send = mutation({
  args: { body: v.string(), author: v.string() },
  handler: async (ctx, { body, author }) => {
    await ctx.db.insert("messages", { body, author })
  },
})

On the client, you use useQuery and it stays live:

const messages = useQuery(api.messages.list)
// messages updates automatically when data changes

The Convex reactive model eliminates the need to manually manage websocket connections, invalidate caches, or write polling logic. It is the most developer-friendly real-time experience of the three options.

Supabase Architecture

Supabase wraps PostgreSQL with a REST API (PostgREST), a GraphQL API, and a realtime engine built on Elixir and Phoenix Channels. The realtime layer listens to the Postgres Write-Ahead Log (WAL) and broadcasts changes to subscribed clients.

// Supabase realtime subscription
const supabase = createClient(url, anonKey)

const channel = supabase
  .channel("messages")
  .on(
    "postgres_changes",
    { event: "INSERT", schema: "public", table: "messages" },
    (payload) => {
      setMessages((prev) => [...prev, payload.new])
    }
  )
  .subscribe()

The Supabase realtime model gives you change events from the database. You receive notifications of what changed and update your UI accordingly. It is less automatic than Convex (you manage the local state update) but it is battle-tested at scale and works with the full power of PostgreSQL — joins, indexes, full-text search, and complex queries.

Firebase Architecture

Firebase Firestore uses real-time listeners that fire whenever the underlying NoSQL document changes. The SDK abstracts away websocket management:

import { collection, onSnapshot, query, orderBy } from "firebase/firestore"

const q = query(collection(db, "messages"), orderBy("createdAt", "desc"))
const unsubscribe = onSnapshot(q, (snapshot) => {
  const messages = snapshot.docs.map((doc) => ({
    id: doc.id,
    ...doc.data(),
  }))
  setMessages(messages)
})

Firebase's realtime is built on Google's proprietary WebSocket infrastructure and is famously fast for document-level changes. Offline support for mobile apps is best-in-class — Firebase caches data locally and syncs when connectivity is restored, which is why it remains dominant in mobile SaaS applications.

Realtime Performance

Benchmarks from independent tests in 2026:

MetricConvexSupabaseFirebase
P50 update latency~20ms~50ms~30ms
P99 latency (5,000 concurrent)<50ms100–200ms<100ms
Offline supportNoNo (partial)Yes (Firestore)
Reactive queriesYes (automatic)Manual subscriptionManual onSnapshot

Convex sustains sub-50ms read/write latency at 5,000 concurrent connections. Supabase can see 100–200ms P99 latencies under similar load because the WAL-based realtime engine has higher processing overhead than Convex's purpose-built reactive system. Firebase Realtime Database (not Firestore) is the fastest for simple key-value subscriptions but is limited in query capability.

Pricing Comparison

Convex

The Convex free plan supports up to 6 developers working on 20 projects with 1 million function calls per month, 20 GB-hours of compute, and basic database and file storage. Convex Pro is priced per seat with additional charges for function execution overage.

Cost model: Compute-based (function execution time and calls). Costs scale with app usage, not data volume.

Supabase

The Supabase free tier gives you 2 projects with 500 MB database, 5 GB bandwidth, and 50,000 monthly active users. Supabase Pro is $25/month per project with 8 GB database, 250 GB bandwidth, and 100,000 MAU. Team plan is $599/month for SOC2 compliance and priority support.

Cost model: Service usage (database size, bandwidth, MAU). Most production apps land at $35–75/month after factoring in overages. At 500,000 MAU, auth costs alone reach $1,300/month.

Firebase

Firebase (Google Cloud) uses a pay-as-you-go model for Firestore: $0.06 per 100,000 reads, $0.18 per 100,000 writes, $0.02 per 100,000 deletes, plus $0.18 per GB stored. The Spark free plan is generous for development. Costs at scale can be unpredictable — high-read applications can generate large bills because every Firestore query counts individual document reads.

Cost model: Operations-based (reads/writes/deletes). Firebase is the most expensive at scale for read-heavy applications. Supabase Pro at $25/month is 4–5x cheaper for equivalent usage in most SaaS workloads.

Developer Experience Comparison

FactorConvexSupabaseFirebase
TypeScriptNativeGoodPartial
Schema definitionTypeScript typesSQL + Drizzle/PrismaNoSQL (schemaless)
Query languageTypeScript APISQLFirestore Query API
Local devConvex dev serversupabase CLIFirebase emulator
Type safetyEnd-to-endPartial (via ORM)Limited
Learning curveLowMediumMedium
Self-hostingNoYesNo
Open sourceNoYesNo

Convex's TypeScript-native approach gives the tightest end-to-end type safety. Your database schema, server functions, and client queries share types without a code generation step. Supabase achieves similar type safety when you use Drizzle ORM or Prisma on top of the PostgreSQL layer — but this requires more setup. Firebase's Firestore is schemaless, which trades type safety for flexibility.

Auth Comparison

Convex Auth (convex-auth package): Provides email/password and OAuth flows built on top of Convex's data model. Relatively new compared to Supabase or Firebase Auth.

Supabase Auth: Full-featured authentication with email/password, magic links, OAuth (50+ providers), phone OTP, and SAML/SSO for enterprise. Row Level Security integrates directly with Supabase Auth, so your database access policies are co-located with your schema.

Firebase Auth: The most mature mobile auth SDK available. Social login, phone auth, anonymous auth, and deep integration with Firebase security rules. If you are building a mobile app with React Native or Flutter, Firebase Auth has the best native SDK support.

SaaS Boilerplate Ecosystem

All three backends have SaaS boilerplate support, but the ecosystems differ significantly:

Supabase has the largest boilerplate ecosystem. Nearly every major Next.js SaaS starter supports Supabase. See our best SaaS boilerplates with Supabase guide for the full list.

Convex has a growing set of dedicated starters. See the best Convex boilerplates guide for Convex-specific options.

Firebase has mature support in older boilerplates and strong React Native/Flutter starter coverage, but is less common in the latest Next.js SaaS starters — most have migrated to Supabase.

For a comparison that includes PocketBase as a self-hosted alternative, see our Convex vs Supabase vs PocketBase comparison.

When to Choose Each

Choose Convex When

  • You are building a highly interactive, real-time SaaS product (collaborative tools, live dashboards, multiplayer features)
  • Your team is TypeScript-only and wants end-to-end type safety with zero SQL
  • You want the simplest possible reactive data model without managing websocket subscriptions
  • You are building a product where real-time UX is a core differentiator

Avoid Convex if: You need self-hosting, SQL-based analytics, complex relational joins, or an open-source backend.

Choose Supabase When

  • Your SaaS is data-intensive with complex relational queries
  • You need PostgreSQL's power (full-text search, PostGIS, pg_vector for AI features)
  • Open source and self-hostability are requirements
  • You want Row Level Security to enforce access control at the database level
  • Your team is SQL-familiar or uses an ORM like Prisma or Drizzle

Avoid Supabase if: Your primary use case is simple document storage with heavy real-time updates at scale, or if your team has no SQL experience.

Choose Firebase When

  • You are building a mobile-first SaaS (React Native, Flutter, native iOS/Android)
  • Offline support is a product requirement
  • You are already in the Google Cloud ecosystem
  • You need the most mature and battle-tested mobile auth SDK available

Avoid Firebase if: You are building a web-only SaaS, you are cost-sensitive at scale, or you want to avoid vendor lock-in (Firebase is proprietary and cannot be self-hosted).

Migration Complexity

If you choose wrong and need to migrate:

Supabase → Firebase or Convex: Supabase exports PostgreSQL dumps. Migrating to Convex requires rewriting queries to the Convex API. Migrating to Firebase requires transforming relational data to a document model.

Firebase → Supabase: The most common migration path in 2026 as teams move from Firebase's NoSQL to PostgreSQL for better query capability. Firebase exports JSON; Supabase provides migration tools for common document-to-relational patterns.

Convex → anything: Convex exports data as JSON. No SQL schema to migrate, but you lose the reactive query model and need to rebuild subscriptions.

The safest long-term choice for migration flexibility is Supabase, because PostgreSQL is portable and the export format is standard.

Final Recommendation

For most SaaS starters in 2026: Supabase. The combination of PostgreSQL reliability, open-source freedom, mature auth, and the largest boilerplate ecosystem makes it the default choice. It is also the most cost-predictable at scale.

For real-time-first products: Convex. If your SaaS is built around live collaboration, reactive dashboards, or multiplayer features, Convex's reactive query model is worth the tradeoff of no SQL and no self-hosting.

For mobile-first products: Firebase. If most of your users are on mobile and offline support matters, Firebase Auth and Firestore are still the strongest mobile backend combination available.

Start with Supabase unless your use case clearly maps to Convex or Firebase. The boilerplate ecosystem, the available tooling, and the exit options are all superior.

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