Anonymous

A throwaway user and session for visitors who have not signed up. When the same visitor later authenticates for real, the anonymous account is linked via on_link_account and cleaned up. Mirrors the TS anonymous() plugin.

Enable

from better_auth import BetterAuth
from better_auth.plugins_ext import AnonymousPlugin

auth = BetterAuth(
    secret="a-strong-32-character-minimum-secret",
    plugins=[AnonymousPlugin(email_domain_name="example.com")],
)

Options

Option	Type	Default	Description
email_domain_name	str | None	None	Domain for the generated placeholder address (temp-<id>@<domain>); without it, <id>@anonymous.placeholder.invalid.
on_link_account	callable | None	None	({"anonymousUser": ..., "newUser": ...}) -> None, called when the visitor signs up for real.
disable_delete_anonymous_user	bool	False	Keep the anonymous user row after linking.
generate_name	callable | None	None	Custom display-name generator, (ctx) -> str.
generate_random_email	callable | None	None	Custom placeholder-email generator.

Endpoints

Method	Path
POST	/sign-in/anonymous
POST	/delete-anonymous-user

Schema

Table	Added columns
user	isAnonymous

Notes

• An anonymous user cannot sign in anonymously again (ANONYMOUS_USERS_CANNOT_SIGN_IN_AGAIN_ANONYMOUSLY).
• When user.validate_user_info is set, it runs before the anonymous user is created, with source set to {"action": "create-user", "method": "anonymous"}.
• Deliberate simplification: the TS per-instance schema field-name override is not exposed.

Changed in 1.1

Without email_domain_name, new anonymous users get <id>@anonymous.placeholder.invalid instead of temp@<id>.com. Existing users keep their email. Code that detects anonymous users by the old email pattern should check the isAnonymous column instead. See Upgrade from 1.0.