Up to date documentation can be found in the postman documentation:
The UNS API is organized around REST. The API has predictable resource-oriented URLs, accepts application/json request bodies, returns JSON-encoded responses, and uses standard HTTP response codes, authentication, and verbs.
You can use the UNS API in a Sandbox environment, which doesn't affect your live data or interact with any external service which can infer any extra costs. The API key you use to authenticate the request is a different one from Sandbox environment and production, additionally, both environments are clearly separated by a different base URL.
UNS API compromises to maintain some old versions to allow the developer to migrate their services to a newer API version.
Updated 8 months ago