Expert Answer: RESTful API design follows REST principles: use HTTP methods correctly (GET, POST, PUT, DELETE), design resource-based URLs, return appropriate status codes, implement proper error handling, use JSON for data exchange, and ensure stateless communication.
Example: Design user management endpoints:
GET /api/users - List all users
GET /api/users/123 - Get specific user
POST /api/users - Create new user
PUT /api/users/123 - Update user
DELETE /api/users/123 - Delete user
Always use nouns for resources, not verbs. Implement proper status codes (200 for success, 404 for not found, 400 for bad request, 500 for server errors).