What are the main differences between REST and GraphQL?

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REST and GraphQL are two different approaches to building APIs, each with its own strengths and weaknesses.

Key Differences

1. Data Fetching

• REST: Fetches fixed data structures from predefined endpoints.
• GraphQL: Allows clients to specify exactly what data they need, reducing over-fetching and under-fetching.

2. Endpoint Structure

• REST: Multiple endpoints for different resources (e.g., /users, /posts).
• GraphQL: Single endpoint for all queries and mutations.

3. Versioning

• REST: Often requires creating new versions of endpoints (e.g., /v1/users, /v2/users).
• GraphQL: Typically does not require versioning; clients request exactly the fields they need, even as the schema evolves.

4. Performance

• REST: May result in multiple round trips to fetch related resources, leading to higher latency.
• GraphQL: Can fetch all required data in a single request, potentially improving performance.

5. Error Handling

• REST: Relies on HTTP status codes for error handling.
• GraphQL: Uses a standardized error object within the response, which can include multiple errors.

Use Cases

• REST: Suitable for simpler applications with well-defined resource structures and less complex querying needs.
• GraphQL: Ideal for applications requiring complex queries and interactions between multiple data sources.

Common Pitfalls

• REST: Over-fetching or under-fetching data, managing multiple endpoints.
• GraphQL: Complexity in setting up the server, potential for inefficient queries if not optimized.

# Example GraphQL Query
{
  user(id: "1") {
    name
    posts {
      title
    }
  }
}