| Product | Convex |
| Website | convex.dev |
| Category | Backend Platform / Reactive Database |
| Pricing | Free tier, then usage-based |
What Is Convex?
Convex is a reactive backend platform that replaces your database, server functions, file storage, and real-time sync in one service. You write server functions in TypeScript, queries automatically re-run when data changes, and the client stays in sync without polling, WebSockets setup, or cache invalidation. The entire backend is type-safe from database to client.
The reactive model means your UI always shows the latest data. When a mutation changes a record, every query that reads that record re-runs and pushes the updated result to every connected client. This is what makes collaborative apps, dashboards, and real-time features feel instant.
Key Features
Reactive Queries
Write a query function that reads from the database. Convex tracks which documents the query reads. When any of those documents change, the query re-runs and the new result is pushed to all subscribed clients. No polling, no manual cache invalidation, no WebSocket boilerplate.
Server Functions
Mutations and actions run on Convex’s servers. Mutations are transactional and deterministic — they read and write the database with ACID guarantees. Actions can call external APIs, send emails, and perform side effects. Both are TypeScript functions with full type safety.
Scheduled Functions
Schedule a function to run at a specific time or after a delay. Use it for reminder emails, delayed processing, recurring jobs, and timeout handling. The scheduler is built into the platform — no separate cron service needed.
File Storage
Upload and serve files through Convex. Files are stored alongside your data and accessible through the same type-safe API. No S3 bucket to configure, no CDN to set up, no signed URL logic to write.
Who Is This For?
- Developers building real-time collaborative applications
- Teams that want a complete backend without managing infrastructure
- Rapid prototypers who want to go from idea to working app in hours
- Anyone tired of gluing together a database, API, file storage, and real-time sync
Pros
- Reactive queries (real-time sync built in)
- End-to-end type safety
- Database, functions, file storage in one platform
- ACID transactions
- Generous free tier
- Fastest path from idea to working backend
Cons
- Strong vendor lock-in (proprietary database)
- Not SQL (document-based with custom query language)
- Self-hosting limited (recent open-source release)
- Reactive model has a learning curve
- Less ecosystem than Supabase or Firebase
Verdict
Convex is the most productive way to build a real-time backend. The reactive query model eliminates the entire category of cache invalidation bugs, the end-to-end type safety catches errors before they ship, and the all-in-one platform means one service instead of five.
The trade-off is lock-in: Convex’s database is proprietary, and the reactive programming model is specific to Convex. Moving to another backend means rewriting your data layer. For applications where real-time collaboration is a core feature, the productivity gains justify the lock-in. For CRUD apps that don’t need real-time, simpler options (Supabase, a Postgres instance) may be enough.
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