GraphQL

GraphQL is an API style where the client can request exactly the fields it needs.

Instead of multiple endpoints (/users, /users/:id, /users/:id/posts), GraphQL often exposes a single endpoint (commonly /graphql) and the client sends queries.

Where GraphQL Is Used

• Frontends that need flexible queries (complex pages, many UI components)
• Public APIs where clients need different shapes of the same data

Industry Examples (Companies)

• GitHub: GraphQL API for developer/platform integrations
• Shopify: GraphQL Admin API
• Meta (Facebook): created GraphQL and uses it heavily

Pros / Cons

Pros:

• Reduces over-fetching/under-fetching (client chooses fields)
• Strong typing via schema
• Great developer experience with tooling

Cons:

• Caching can be harder than REST (queries vary)
• You still need to design your schema carefully
• Performance pitfalls (e.g., N+1 queries) if resolvers are naive

Tiny Example

Query:

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

Response:

{
  "data": {
    "user": {
      "id": 42,
      "name": "Alice",
      "posts": [{ "id": 1, "title": "Hello" }]
    }
  }
}

References

• GraphQL