GraphQL

GraphQL vs REST

REST: GET /users/42 returns the entire User object — the client uses only name. GraphQL: query { user(id: 42) { name } } — the server returns only name. One endpoint instead of dozens.

Key concepts

• Query — reading data
• Mutation — changing data
• Subscription — real-time via WebSocket
• Schema — a typed contract between client and server

When to choose GraphQL

Ideal for mobile clients (minimal traffic), complex nested data, and when multiple clients have different data needs. REST is simpler for straightforward CRUD.