Convex Expert Guide - December 2025

What is Convex?

Convex is a full-stack TypeScript backend platform with:

• Reactive database - Real-time subscriptions, automatic cache invalidation
• Serverless functions - Queries, mutations, actions with TypeScript
• ACID transactions - Every mutation is a transaction, automatic conflict resolution
• Type safety - End-to-end types from schema to React hooks
• Built-in features - Auth, file storage, scheduling, vector search, workflows

Function Types

Type	Purpose	Database	External APIs	Deterministic
query	Read data	✅ Read	❌	✅ Required
mutation	Write data	✅ Read/Write	❌	✅ Required
action	Side effects	Via runQuery/runMutation	✅	❌
httpAction	HTTP endpoints	Via ctx	✅	❌