# Why Use Access Tokens?
When a bidder registers for online bidding, they set up a password associated with their email address. They can use this to sign in from anywhere.
You can also send bidders a Bidder Invitations which is an email with a personalized link to the auction web site to facilitate the registration process.
However, when registering bidders at an event during check-in it is cumbersome to get them to set up a password for online bidding then and there.
Bidder Access Tokens allow the bidder to access the auction website and bid without having to sign in or even set up a password. The bidder can be manually registered from the dashboard, with their email address, and be sent an email which contains a link that will sign the bidder into the web site.
However, bidders can only sign in this way using devices where they have access to their email.
The email will also contain a bidder access code, which is a 5 or 6 character code assigned by the system, the bidder can use to sign into the website, or the mobile app. You can also provide this code to the bidder by writing it down so they can use it even if they cannot access email on their device.
For security reasons, Access Token will expire after 10 days.