Max size of custom user attribute in keycloak

Question

What is the max size of a custom user attribute in KeyCloak? The official doc only describes how to create such attributes. If the size is limmited to 255 characters as default size of the string in a database then is there an ability to configure this size not modifying the source code?

Answer 1

Keycloak's attribute values maximum length is defined by its backend storage. The default setup uses PostgreSQL. Custom user attributes are stored in user_attribute table, which has value of type varchar(255).

You may want to change the field type to text. Please make sure to backup your database first.

ALTER TABLE user_attribute ALTER COLUMN value TYPE TEXT;