# API Usage Guidelines

Public cloud APIs comply with the RESTful API design principles. REST-based web services are organized into resources. Each resource is identified by one or more Uniform Resource Identifiers (URIs). An application accesses a resource based on the resource's Unified Resource Locator (URL). A URL is usually in the following format: https://Endpoint/uri. In the URL, uri indicates the resource path, that is, the API access path.

An endpoint is the request address for calling an API. Endpoints vary depending on services and regions. For DNS endpoints, see Regions and Endpoints.

- Private zone APIs and related APIs call different endpoints based on the region.

  For example, call the API provided in Private Zone Management to create a private zone, and call the API provided in Record Set Management to add a record set to a private zone.

- Public zone APIs, PTR record APIs, and related APIs call only endpoint dns.eu-de.otc.t-systems.com in the eu-de region.

  For example, call the API provided in Public Zone Management to create a public zone, call the API provided in Record Set Management to add a record set to a public zone, and call the API provided in PTR Record Management to add a PTR record.

Public cloud APIs use HTTPS as the transmission protocol. Requests/Responses are transmitted using JSON messages, with the media type represented by Application/json.

For details about how to use APIs, see API Usage Guidelines.