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DeveloperIntroduction to GraphQL

Introduction to GraphQL

If you’re familiar with REST APIs, think of GraphQL as an alternative way to fetch and manipulate data from a server. While both technologies serve similar purposes, they approach the problem differently.

Key Differences from REST

1. Single Endpoint vs Multiple Endpoints

REST: Uses multiple endpoints (URLs) like /users, /posts/{id}, /comments GraphQL: Uses a single endpoint for all operations (typically /graphql)

Instead of making multiple requests to different endpoints, you send all your data requirements to one endpoint.

2. Request What You Need vs Fixed Responses

REST: The server decides what data to return

  • Example: GET /users/1 returns a fixed structure with user data
  • If you only need the user’s name and email, you still get everything else too

GraphQL: You specify exactly what you want

query {
  user(id: "1") {
    name
    email
  }
}

You only get the name and email fields - nothing more.

3. No Over-fetching or Under-fetching

REST Problem: You often fetch too much data (over-fetching) or need multiple requests to get related data (under-fetching)

GraphQL Solution:

  • Get exactly the data you need in one request
  • Fetch nested resources without additional requests

Example with nested data:

query {
  user(id: "1") {
    name
    posts {
      title
      comments {
        text
      }
    }
  }
}

4. Strongly Typed Schema

GraphQL has a defined schema that describes:

  • What types of data are available
  • What queries can be made
  • What mutations can be performed

This schema serves as documentation and validation for your API.

GraphQL Operations

Queries (GET-like)

Used to fetch data:

query {
  users {
    id
    name
    email
  }
}

Mutations (POST/PUT/DELETE-like)

Used to modify data:

mutation {
  createUser(name: "Alice", email: "alice@example.com") {
    id
    name
  }
}
Developer DocumentationCreateActivityForUserWithNumbers