If the [authentication process](00001012050200) was successful, an access token with some additional data is returned.
The same is true, if the access token was [renewed](00001012050400).
The response is structured as a [symbolic expression](00001012930000) list, with the following elements:

1. The type of the token, always set to `"Bearer"`, as described in [RFC 6750](https://datatracker.ietf.org/doc/html/rfc6750)
1. The token itself, which is technically the string representation of a [symbolic expression](00001012930500) containing relevant data, plus a check sum.
    * The symbolic expression has the form `(KIND USERNAME NOW EXPIRE Z-ID)`
    * `KIND` is `0` for an API access, `1` if it created for the Web user interface.
    * `USERNAME` is the user name of the user.
    * `NOW` is a timestamp of the current time.
    * `EXPIRE` is the timestamp when the access token expires.
    * `Z-ID` is the zettel identifier of the user zettel.
   The symbolic expression is encoded via “base64”.
   Based on this encoding, a checksum is calculated, also encoded via “base64”.
   Both encoded values are concatenated, with a period (`"."`) as a delimiter.