Convex vs Supabase vs Appwrite: Backend Platforms Compared

Firebase dominated Backend as a Service for years, but its NoSQL database (Firestore), vendor lock-in, and unpredictable pricing pushed developers to seek alternatives. Supabase emerged as the "open-source Firebase alternative" with PostgreSQL at its core. Appwrite carved out the self-hosted niche. And Convex arrived with a fundamentally different approach: a reactive database that treats real-time as the default, not an add-on.

All three platforms promise the same thing: build your backend without managing servers. They provide databases, authentication, file storage, serverless functions, and real-time capabilities. The differences are in architecture, developer experience, and where they excel.

Choosing the right BaaS saves months of backend development. Choosing the wrong one means hitting walls that force you to migrate, which is painful and expensive. Here is an honest comparison to help you pick correctly.

For context on how these compare to Firebase specifically, see our Supabase vs Firebase comparison.

Convex is the most opinionated of the three, and that is its strength. It is built around one idea: your database should be reactive. When data changes, every client viewing that data updates automatically. No WebSocket setup. No subscription management. No cache invalidation. It just works.

How Convex Works

You define your backend in TypeScript: queries, mutations, and actions. Queries are reactive by default. If a component uses a Convex query, it re-renders whenever the underlying data changes. Mutations are transactional and ACID-compliant. Actions handle side effects (calling external APIs, sending emails).

Strengths

• Real-time by default. Every query is a live subscription. No polling, no WebSocket boilerplate. Building a chat app, collaborative editor, or live dashboard is trivially easy.
• End-to-end TypeScript. Schema, queries, mutations, and client code are all TypeScript with full type safety. Change a schema field and TypeScript errors show you every affected query and component.
• Automatic caching and consistency. Convex handles cache invalidation automatically. Mutations update the cache, and dependent queries re-run. No stale data.
• ACID transactions. Unlike Firestore's eventually consistent model, Convex provides real ACID transactions across multiple tables.

Limitations

• Proprietary database. Convex uses its own database engine, not PostgreSQL. You cannot run raw SQL. Migration away from Convex means rewriting your data layer.
• Smaller ecosystem. Fewer tutorials, fewer community plugins, fewer Stack Overflow answers than Supabase.
• Pricing can scale fast. Real-time subscriptions consume more resources than traditional request-response. High-traffic apps with many concurrent subscriptions can hit pricing limits.

Supabase is the most popular Firebase alternative, and for good reason. It gives you a full PostgreSQL database with a REST and GraphQL API auto-generated from your schema, real-time subscriptions, authentication, file storage, and edge functions.

Strengths

• PostgreSQL. A real relational database with full SQL support, joins, indexes, stored procedures, triggers, and the entire PostgreSQL extension ecosystem (PostGIS, pgvector, pg_cron). No proprietary query language.
• Open source. Every component of Supabase is open source. You can self-host the entire stack. No vendor lock-in at the data layer.
• Auto-generated APIs. PostgREST generates a REST API from your database schema. No backend code needed for basic CRUD operations.
• Row-Level Security. PostgreSQL RLS policies let you define access control at the database level. Users can only read/write rows they are authorized to access, enforced by the database itself.
• Generous free tier. 500MB database, 1GB file storage, 50K monthly active users on auth. Enough for most MVPs.

Limitations

• Real-time is an add-on, not a foundation. Supabase Realtime works, but it is built on top of PostgreSQL's LISTEN/NOTIFY, which has performance limits at high throughput. For apps that need thousands of concurrent real-time subscriptions, Convex handles this more elegantly.
• Edge Functions are limited. Supabase Edge Functions run on Deno, which has a smaller ecosystem than Node.js. Cold starts can be noticeable.
• Database management responsibility. You get a PostgreSQL database, which means you are responsible for query optimization, indexing, and connection pooling (via Supavisor). Supabase provides tools, but you need database knowledge.

For a comparison with other PostgreSQL hosting options, see our Neon vs PlanetScale vs Supabase guide.

Appwrite is an open-source BaaS that you can self-host or use as a managed cloud service. It provides the same core features as Supabase (database, auth, storage, functions) with a focus on simplicity and multi-runtime support.

Strengths

• True self-hosting. Deploy Appwrite on your own infrastructure with Docker. Full control over data location, compliance, and costs. Ideal for enterprises that cannot use hosted services.
• Multi-runtime functions. Serverless functions support Node.js, Python, PHP, Ruby, Dart, and more. Use the language your team knows.
• Simple, consistent API. Every SDK (Web, Flutter, React Native, iOS, Android, server-side) follows the same patterns. The API is predictable and well-documented.
• Built-in services. Authentication (OAuth, email/password, phone), database (document-based), storage (with built-in image transformations), functions, and messaging (push notifications, SMS, email) in one package.

Limitations

• Document database. Appwrite uses a document/collection model, not relational SQL. No joins, no complex queries, no PostgreSQL extensions. For simple CRUD, this is fine. For complex data relationships, it is limiting.
• Smaller community. Appwrite's community is a fraction of Supabase's. Fewer tutorials, fewer plugins, fewer third-party integrations.
• Self-hosting overhead. Self-hosting saves money at scale but requires DevOps expertise. Backups, updates, scaling, and monitoring are your responsibility.
• Cloud service is newer. Appwrite Cloud launched later than Supabase's hosted service. The managed offering is less mature, with fewer regions and less infrastructure optimization.

Here is a direct feature-by-feature comparison:

Database

• Convex: Proprietary reactive database. Document-based with relations. ACID transactions. No raw SQL.
• Supabase: PostgreSQL. Full SQL, joins, indexes, extensions (pgvector, PostGIS). The most powerful database option.
• Appwrite: Document database (MariaDB under the hood). Collections and documents. No SQL access.

Real-Time

• Convex: Best in class. Every query is reactive by default. Automatic cache invalidation. Handles thousands of concurrent subscriptions.
• Supabase: Good. PostgreSQL LISTEN/NOTIFY with channel-based subscriptions. Works for moderate real-time needs. Performance ceiling for very high throughput.
• Appwrite: Basic. Real-time events for document changes. Functional but less flexible than Convex or Supabase.

Authentication

• Convex: Integrates with Clerk, Auth0, or custom JWT. No built-in auth UI.
• Supabase: Built-in auth with email, phone, OAuth (Google, GitHub, etc.), and magic links. Auth UI components available.
• Appwrite: Built-in auth with email, phone, OAuth, anonymous, and magic URL. Comprehensive and easy to set up.

File Storage

• Convex: Built-in file storage with upload and serving. Basic but functional.
• Supabase: S3-compatible storage with CDN, image transformations, and RLS policies. The most feature-rich option.
• Appwrite: File storage with built-in image transformations (resize, crop, watermark). Good for common use cases.

Cost at different scales matters for startups planning growth:

Free Tier

• Convex: Generous free tier for development and small projects. Limits on database size, function calls, and bandwidth.
• Supabase: 500MB database, 1GB storage, 50K MAU auth, 500K Edge Function invocations. The most generous free tier.
• Appwrite: Free self-hosted (infrastructure costs only). Cloud free tier includes limited resources.

Growth Stage (10K MAU, moderate usage)

• Convex: Pro plan at $25/month plus usage. Real-time heavy apps may need the Team plan.
• Supabase: Pro plan at $25/month. Includes 8GB database, 100GB storage, and increased limits.
• Appwrite: Self-hosted: $50 to $150/month in infrastructure. Cloud: comparable to Supabase pricing.

Scale Stage (100K+ MAU, high traffic)

• Convex: Team/Enterprise pricing. Can get expensive with many real-time subscriptions.
• Supabase: Team plan at $599/month. Enterprise for higher needs. Database size and egress are the main cost drivers.
• Appwrite: Self-hosted scales linearly with infrastructure costs. No per-seat or per-usage platform fees. Most cost-effective at scale if you have DevOps capability.

Choose based on your product's primary need:

Choose Convex when: Real-time is core to your product (collaborative tools, live dashboards, chat, multiplayer). You want the simplest possible developer experience with TypeScript. You are building a new product and do not need PostgreSQL-specific features. You value automatic reactivity over manual subscription management.

Choose Supabase when: You need a real relational database with full SQL. You want the largest community and ecosystem. You need PostgreSQL extensions (pgvector for AI, PostGIS for location). You want the option to self-host or migrate to raw PostgreSQL later. You are building a typical SaaS, marketplace, or content platform.

Choose Appwrite when: Self-hosting is a requirement (compliance, data sovereignty, cost control). You want a multi-language backend (Python, PHP, Ruby functions alongside your frontend). You need a simple, predictable API across all platforms. Budget is tight and you have DevOps skills to manage infrastructure.

For most startups building a SaaS product in 2026, Supabase is the safest default. PostgreSQL is the most versatile database, the community is the largest, and the exit strategy (migrate to raw PostgreSQL) is the cleanest. Choose Convex if real-time is your killer feature. Choose Appwrite if self-hosting is non-negotiable.

If you need help choosing the right backend platform and architecture for your product, book a free strategy call with our team.