# Authentication

Token authentication must be performed to call APIs.

Authentication using tokens: General requests are authenticated using tokens.

#### Token-based Authentication

The validity period of a token is 24 hours. When using a token for authentication, cache it to prevent frequently calling the IAM API used to obtain a user token.

A token specifies temporary permissions in a computer system. During API authentication using a token, the token is added to requests to get permissions for calling the API.

In Making an API Request, the process of calling the API used to obtain a user token is described.

After a token is obtained, add the X-Auth-Token header field must be added to requests to specify the token when calling other APIs. For example, if the token is ABCDEFJ...., X-Auth-Token: ABCDEFJ.... can be added to a request as follows:

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    Content-Type: application/json
    X-Auth-Token: ABCDEFJ....

Parent topic: Calling APIs