API design principles that developers actually appreciate

An API is a user interface

Developers are your users. An API is their interface to your system. Like any user interface, it should be intuitive, consistent, and forgiving. The best APIs feel invisible — developers accomplish their goals without consulting documentation.

The worst APIs generate support tickets, frustration, and workarounds that create technical debt for both you and your consumers.

Principles we follow

Consistency over cleverness. Use the same patterns for similar operations. If GET /users/{id} returns a user object, GET /orders/{id} should return an order object with the same structure. Deviations force developers to memorise exceptions.

Errors that help. A 400 error with "Bad Request" tells the developer nothing. A 400 error with "Invalid email format: expected user@domain.com" tells them exactly what to fix. Every error response should include a machine-readable error code and a human-readable message.

Pagination by default. Any endpoint that returns a list must support pagination. Returning unbounded lists is a reliability risk — a spike in data volume can crash your API and your consumer's application.

Versioning from day one. Version your API in the URL (/v1/users) or via headers. Breaking changes require a new version. Deprecation warnings should appear six months before removal.

Documentation as a product

Your API documentation is not a reference — it is a sales tool. Interactive examples, quickstart guides, and copy-pasteable code snippets convert more developers than any marketing page. We treat documentation as a first-class product with its own sprint cycle.