API Documentation Standards & Developer Handover
If your project includes APIs — whether consumed by your own systems or exposed for third-party integration — thorough documentation is essential. This article explains our standards.
What We Document
- Endpoint reference: Every endpoint, including URL, HTTP method, request parameters, request body schema, response schema, and possible error codes
- Authentication: How to authenticate against the API (API keys, OAuth 2.0, JWT — with examples)
- Rate limiting: Any rate limits, throttling behaviour, and how to handle 429 responses
- Versioning: How the API version is indicated and what the version support policy is
- Webhooks: If the API sends webhooks, the event types, payload schemas, and signature verification
- Changelog: A log of breaking and non-breaking changes by version
Documentation Format
We use OpenAPI 3.x (formerly Swagger) as our standard for REST API documentation. This format is machine-readable (enabling automatic client SDK generation) and human-readable. We provide both an interactive Swagger UI and a downloadable specification file.
Developer Handover Pack
At project handover, developers inheriting your system receive:
- The OpenAPI specification
- Postman collection with sample requests for every endpoint
- A getting-started guide covering authentication and first API call
- Test credentials for a sandbox environment (where available)
Keeping Documentation Current
Outdated documentation is worse than no documentation — it causes integration errors. Our CI/CD pipeline enforces that API documentation is updated as part of any API change, not as an afterthought.