Top 8 Tips For Restful API Design

Domain Model Driven
Structure your API around meaningful entities in your domain model. For example, use resource relationships like /orders/{id}/items to clearly indicate connections between resources, such as orders and their items. A well-organized model makes your API more intuitive and reduces ambiguity.

Choose HTTP Methods Wisely
Use HTTP methods according to their intended purpose:
GET: For reading data.
POST: For creating new resources.
PUT: For updating resources.
DELETE: For deleting resources.
Avoid using non-standard HTTP methods like PATCH unless absolutely necessary, as they can introduce complexity.

Implement Idempotency Properly
Ensure operations can be retried safely:
GET: Naturally idempotent (no side effects).
PUT and DELETE: Should be designed to be idempotent, meaning repeated calls have the same effect as a single call.
POST: Implement idempotency based on business requirements if needed, especially for sensitive operations.

Choose HTTP Status Codes Thoughtfully
Use standard HTTP status codes to communicate results:
201: Resource created successfully.
400: Validation failed.
401: Authentication required.
403: Permission denied.
404: Resource not found.
500: Server error.
Choosing the right status codes makes error handling clearer for clients.

Versioning
Version your API to support future changes:
Path (recommended): /v1/users
Query: /users?v=1
Header: Use Version:v1 in headers.
This approach avoids breaking changes and supports backward compatibility.

Use Semantic Paths
Design URLs to be meaningful and clear:
Use nouns (not verbs) to represent resources: /usersinstead of /getUsers.
Use plural nouns for collections (e.g., /orders) and singular nouns for individual items (e.g.,/orders/{id}).
Example: /v1/orders/{id}/items for accessing items in an order.

Support Batch Processing
Enable efficient operations by supporting batch requests:
Single Transaction: Process individual requests (e.g., POST /v1/users).
Batch Transaction: Process multiple requests at once (e.g., POST /v1/users/batch).
This minimizes network requests and enhances performance for clients that need to handle multiple resources at once.

Implement Query Parameters for Flexibility
Support query parameters to enhance filtering, pagination, and sorting:
Pagination: GET /v1/users?page=1&size=20
Sorting: GET /v1/users?sort=name.asc,age.desc
Filtering: GET /v1/users?age=gt.20&name=match:Lisa
This approach allows clients to retrieve precisely the data they need, reducing unnecessary data transfers.