Adding Username for Database Connections
For database connections, you can have your users sign in with a username instead of their email address.
Require username
Go to Auth0 Dashboard > Authentication > Database, and select the name of the connection you want to edit.
Locate Requires Username, and use the toggle to enable or disable requiring a username.
To see how this will affect the login screen, select the Try Connection view. Notice that once Requires Username is enabled, new users must enter a username and their email address to sign up.
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Users can then login with either their username or their email address. Users who registered while Requires Username was disabled will not have a Username field stored and will have to log in with their email address.
Username length
The default allowed length for usernames is between 1 and 15 characters. However, using the Auth0 Dashboard or via the Management API v2, you can modify the length minimum and maximum (up to a maximum length of 128 characters).
Allowed characters
The username field accepts the following characters:
Alphanumeric characters (without accent marks, automatically converted to lowercase);
The at sign (@) character (but email addresses are not allowed);
The caret (^) character;
The dollar sign ($) character;
The dot (.) character;
The exclamation (!) character;
The grave accent (\`) character;
The minus (-) character;
The number sign (#) character;
The plus (+) character;
The single quote (') character;
The tilde (~) character;
The underscore (_) character;
No other characters/symbols are allowed, and Auth0 does not validate or sanitize custom database inputs.