# Returned Values

#### Status Code

After sending a request, you will receive a response containing the status code, response header, and response body.

A status code is a group of digits, ranging from 1xx to 5xx. It indicates the status of a request. For more information, see Status Code.

If status code 201 is returned for the calling of the API for obtaining a user token, the request is successful.

#### Response Header

A response header corresponds to a request header, for example, Content-Type.

Figure 1 shows the response header for the API of obtaining a user token, where x-subject-token is the desired user token. Then, you can use the token to authenticate the calling of other APIs.

Figure 1 Header of the response to the request for obtaining a user token

#### Response Body

A response body is generally returned in a structured format, corresponding to the Content-Type in the response header, and is used to transfer content other than the response header.

The following shows part of the response body for the API of obtaining a user token.

    {
        "token": {
            "expires_at": "2019-02-13T06:52:13.855000Z",
            "methods": [
                "password"
            ],
            "catalog": [
                {
                    "endpoints": [
                        {
                            "region_id": "xxx",
    ......

If an error occurs during API calling, the system returns an error code and a message to you. The following shows the format of an error response body:

    {
        "error_msg": "The format of message is error",
        "error_code": "AS.0001"
    }

In the preceding information, error_code is an error code, and error_msg describes the error.

Parent topic: Calling APIs