An API is a contract between systems, and like any contract, clarity matters more than cleverness. A well-designed RESTful API reduces integration time, lowers support overhead, and makes your platform more attractive to third-party developers. A poorly designed one creates confusion that compounds with every new consumer. Here are the practices that separate the two.
Use Nouns for Resources, Verbs for Actions
Endpoints should represent resources, not operations. Use /orders instead of /getOrders, and let HTTP methods convey intent: GET to read, POST to create, PUT or PATCH to update, DELETE to remove. This convention is widely understood and allows clients to predict behavior without reading documentation for every endpoint.
Be Consistent With Naming and Structure
Pick a naming convention — camelCase or snake_case — and stick with it across every endpoint and response field. Consistency extends to pagination, filtering, and error formats as well. If one endpoint returns errors in a { "error": { "code": 422, "message": "..." } } structure, every endpoint should do the same. Inconsistency forces consumers to write special-case handling, which is a reliable source of bugs.
Version Your API From Day One
Breaking changes are inevitable. Embedding a version prefix like /v1/ in the URL is the simplest approach and the easiest for consumers to understand. Header-based versioning is more elegant in theory but harder to test with a browser or curl. Whichever strategy you choose, commit to supporting previous versions for a documented deprecation period.
Return Meaningful Status Codes and Errors
A 200 response with { "success": false } in the body is an anti-pattern that frustrates every client developer who encounters it. Use 201 for created resources, 204 for successful deletions with no body, 400 for validation errors, 404 for missing resources, and 409 for conflicts. Pair status codes with human-readable error messages and, where possible, machine-readable error codes that clients can switch on programmatically.
Design for Evolution
Additive changes — new optional fields, new endpoints — are safe. Removing or renaming fields is not. Design responses with this in mind: use envelope objects so you can add metadata later, and avoid returning raw arrays at the top level. Thinking about forward compatibility during the initial design saves expensive migration efforts down the road.