Technical reference
Every service in one description. What holds for one holds for all.
APIzone has one interface, not one per service. Authentication, versioning, billing, idempotency and the error object are the same everywhere. Once you have integrated one service, integrating the next takes as long as reading its fields.
Below you find the complete description: every operation with its parameters, every response with its structure, every error code your application may branch on. Services are grouped by area, with the shared part at the top.
The file is authoritative, not this rendering. It lives in the repository, is maintained in the same change set as the code, and can be used to generate clients. If the service deviates from it, the service is wrong.