Evolution of Data Fetching

In traditional REST APIs, the JSON structure is fixed by the server. GraphQL allows clients to specify exactly what fields they need using a JSON-like query language.

Query Example

{
  user(id: "1") {
    name
    friends {
      name
    }
  }
}

Response

The response strictly follows the query structure:

{
  "data": {
    "user": {
      "name": "Alice",
      "friends": [{ "name": "Bob" }]
    }
  }
}

Type System and JSON

GraphQL's strong type system addresses JSON's loose typing. The Schema Definition Language (SDL) defines types for every field, ensuring contract certainty.

Performance Considerations

• Avoid Over-fetching: Fetch only what is needed, reducing payload size.
• Avoid Under-fetching: Get related data in a single request, reducing RTT.

Summary

GraphQL combines JSON's flexibility with a strong type system, providing a more efficient solution for data interaction in complex applications.