Salesforce Sites guest user characteristics

Guest User License Characteristics

1. Each site has a special user with a user type called "guest user."
2. Guest users have no password, no role, and no API access on their profile.
3. You cannot log in or make client-side API calls as a guest user (API calls are only permitted from within Apex code).
4. There is no session for guest browsing.
5. Each guest user (site) has a unique profile (Public Access Settings).

Access and Permissions

1. Guest user profiles are associated with guest user licenses, which grant the ability to read and create on standard objects and full CRUD access on custom objects. By default, no CRUD access is granted — admins must enable the appropriate access level based on their use case.
2. Salesforce recommends using private sharing for objects that are enabled for Sites access.
3. Guest user licenses cannot be used for any purpose other than Force.com Sites.

Metadata API Restriction

1. Custom Profiles with a Guest User License cannot be added to any Metadata API deployment method, including Changesets, the Force.com IDE, or ANT.