# Access token format

> Learn the structure and components of an access token.

A Vivox access token is similar to a JSON Web TokenClosed (JWT), but with a limited set of claims, for example, `vxi, f, iss, vxa, t, exp`.

The Vivox access token is a string that uses the format `header.payload.signature`: three base64url-encoded parts that are separated by periods.

> **Note:**
>
> Base64url encoding is not the same as Base64 encoding. For more information, refer to [Access token terminology](./access-token-terminology).