GraphQL and REST are two popular paradigms for building APIs, each with its own strengths and use cases.

REST (Representational State Transfer):

• Uses standard HTTP methods: GET, POST, PUT, DELETE.
• Resource-based architecture (e.g., /users/1/posts).
• Multiple endpoints required for complex data queries.

Pros:

• Simple and widely understood.
• Caching is straightforward (via HTTP).
• Mature ecosystem.

Cons:

• Over-fetching or under-fetching data.
• Changes in front-end needs may require new endpoints.

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GraphQL:

• Query language developed by Facebook.
• Clients request exactly the data they need in a single call.
• Uses a single /graphql endpoint.

Pros:

• Flexible and efficient data retrieval.
• Ideal for complex, nested data (e.g., social graphs).
• Strongly typed schema enables introspection and documentation.

Cons:

• More complex to set up.
• Caching and error handling require custom strategies.
• Not suitable for all use cases (e.g., file uploads).

Use GraphQL when front-end flexibility is crucial or data relationships are complex. Use REST when simplicity, scalability, and widespread tooling are more important.