GraphQL

GraphQL is a query language for APIs, plus a server runtime that executes those queries against a typed schema. Instead of many fixed endpoints, a client sends one query to a single URL and names the exact fields it needs.

Why it matters

With a REST API, a screen may need three requests that each return more data than required. GraphQL lets the client fetch a user and their latest posts in one round trip and receive only the requested fields, which helps on slow mobile networks. The schema also serves as living documentation.

Example

query {
  user(id: 42) {
    name
    posts(first: 2) { title }
  }
}

The response mirrors the query shape:

{"data": {"user": {"name": "Asha", "posts": [{"title": "Hello"}]}}}

Common mistakes

• Assuming HTTP status codes show failures; GraphQL often returns 200 with an errors array, so monitor the body.
• Allowing unbounded nested queries, which can overload the server. Add depth and cost limits.
• Exposing introspection and verbose errors in production without thinking about who can see them.

Related

• API
• REST API
• JSON
• Rate limiting

This page is general information written by our editorial team and updated when documentation changes. Servers and providers differ, so test changes safely first. See our editorial policy and disclaimer.