Good API design reduces friction for consumers and makes your service easier to maintain. REST APIs built on HTTP have well-established conventions — following them saves developers from having to re-learn your interface from scratch.

Use nouns for resource names, not verbs. /users is correct; /getUsers is not. Keep names lowercase and use hyphens rather than underscores. Nest resources to express hierarchy: /users/123/orders.

Version your API from day one. The most common approach is a URL prefix: /v1/users. Alternative approaches include request headers or query parameters, but URL versioning is the most explicit and cache-friendly.

Return consistent error objects with a machine-readable code, a human-readable message, and an optional details array. Use correct HTTP status codes — 400 for client errors, 500 for server errors.