# Response

#### Status Code

After sending a request, you will receive a response, including 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 Codes.

For example, if status code 201 is returned for calling the API used to obtain a user token (Obtaining a User Token), the request is successful.

#### Response Header

Similar to a request, a response also has a header, for example, Content-Type.

Obtaining a User Token shows the response header fields for the API used to obtain a user token (Figure 1). The x-subject-token header field is the desired user token. This token can then be used to authenticate the calling of other APIs.

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

#### Response Body

The body of a response is often returned in structured format as specified in the Content-Type header field. The response body transfers content except the response header.

The following is part of the response body for the API used to obtain a user token (Obtaining a User Token).

    {
        "token": {
            "expires_at": "2019-02-13T06:52:13.855000Z",
            "methods": [
                "password"
            ],
            "catalog": [
                {
                    "endpoints": [
                        {
                            "region_id": "az-01",
    ......

If an error occurs during API calling, an error code and error description will be displayed. The following shows an error response body:

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

In the response body, error_code is an error code, and error_msg provides information about the error.

Parent topic: Calling APIs