:original_name: waf_02_0001.html

.. _waf_02_0001:

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.

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

For details about how to use APIs, see `API Usage Guidelines <https://docs.otc.t-systems.com/en-us/api/apiug/apig-en-api-180328001.html?tag=API%20Documents>`__.

.. important::

   The following table lists the additional request header fields required for the POST, PUT, PATCH, and DELETE methods.

+-----------------------+-----------------------------------------------+-----------------+-----------------+
| Parameter             | Description                                   | Mandatory       | Example         |
+=======================+===============================================+=================+=================+
| x-request-source-type | Type of a request resource                    | Yes             | ApiCall         |
|                       |                                               |                 |                 |
|                       | -  **ApiCall**: invoked by an API.            |                 |                 |
|                       | -  **ConsoleAction**: invoked by the console. |                 |                 |
|                       | -  **SystemAction**: invoked by the system.   |                 |                 |
+-----------------------+-----------------------------------------------+-----------------+-----------------+