A practical guide to designing clean, consistent REST APIs — resource URLs, correct HTTP methods and status codes, versioning, pagination, and documentation that developers actually enjoy using.
Almost every product today is really a set of APIs with a UI on top. A well-designed API is a pleasure to build against and easy to evolve; a badly designed one becomes a permanent source of bugs and support tickets. Good API design isn't about cleverness — it's about consistency and following conventions developers already expect. Here are the principles we follow when building APIs and integrations for clients.
Core design principles
Model resources, not actions URLs should represent things (nouns), not operations (verbs). Use /orders and /orders/123, not /getOrder or /createOrder. The HTTP method already carries the action.
Use HTTP methods correctly GET reads, POST creates, PUT/PATCH updates, DELETE removes. GET must never change data — a rule that, when broken, causes real bugs with caching and retries.
Return the right status codes 200 for success, 201 for created, 400 for bad input, 401/403 for auth issues, 404 for not found, 422 for validation errors, 500 for server faults. Consistent status codes let clients handle responses correctly without guessing.
Be consistent everywhere Pick conventions — casing, date formats (ISO 8601), pluralization, error shapes — and apply them across every endpoint. Consistency is what makes an API feel intuitive.
Practical best practices
- Version from day one (for example /v1/) so you can evolve without breaking existing clients.
- Paginate list endpoints — never return unbounded lists; use limit/offset or cursor pagination.
- Support filtering and sorting via query parameters for list endpoints.
- Return helpful, consistent errors — a machine-readable code plus a human-readable message, in the same shape everywhere.
- Document with real examples — an OpenAPI/Swagger spec with sample requests and responses saves everyone time.
REST vs. the alternatives
REST remains the pragmatic default for most business applications. GraphQL shines when clients need flexible, nested data (and you control both ends); gRPC suits high-performance internal service-to-service calls. For most SMB products and integrations, a clean REST API is the right, well-understood choice.
Frequently asked questions
Should I use REST or GraphQL? REST for most business APIs and public integrations; GraphQL when clients need to fetch varied, nested data efficiently and you own the clients. Many systems use both.
How should I version an API? URL versioning (/v1/) is the simplest and most transparent. The key is having a version strategy before you have external consumers.
How important is documentation? Critical. An undocumented API is effectively unusable by anyone but its author. An OpenAPI spec with examples is the standard.
Need well-designed APIs or third-party integrations built properly? Talk to us — clean, documented APIs are part of how we build.