GraphQL vs REST: A Practical Comparison for Modern APIs

GET    /api/users/123
GET    /api/users/123/posts
GET    /api/users/123/followers

graphql
query {
  user(id: "123") {
    name
    email
    posts(limit: 5) {
      title
      createdAt
    }
    followers {
      count
    }
  }
}

✅ Simple CRUD applications
✅ File uploads and downloads
✅ Caching (HTTP caching works out of the box)
✅ When your team is small and the API surface is limited
✅ Microservices communication (service-to-service)
✅ Public APIs (easier to document and rate-limit)

✅ Complex, interconnected data (social networks, dashboards)
✅ Mobile applications (minimize data transfer)
✅ Multiple client types (web, mobile, TV) with different data needs
✅ Rapidly evolving frontends
✅ When over-fetching is causing performance issues

typescript
import { ApolloServer } from '@apollo/server';

const typeDefs = `
  type User {
    id: ID!
    name: String!
    email: String!
    posts: [Post!]!
  }
  
  type Post {
    id: ID!
    title: String!
    content: String!
    author: User!
  }
  
  type Query {
    user(id: ID!): User
    posts(limit: Int): [Post!]!
  }
`;

const resolvers = {
  Query: {
    user: (_, { id }) => getUserById(id),
    posts: (_, { limit }) => getPosts(limit),
  },
  User: {
    posts: (user) => getPostsByUserId(user.id),
  }
};

typescript
const userLoader = new DataLoader(async (ids) => {
  const users = await db.users.findMany({ where: { id: { in: ids } } });
  return ids.map(id => users.find(u => u.id === id));
});