Column-level security is a rule that controls which columns a person can see. Everyone might use the same staff table, but only HR sees the salary column; everyone sees the order list, but only finance sees the cost and margin columns. The rest of the page looks identical. The protected column is either removed entirely or masked so the shape is visible but the value is not.
You meet this the first time a spreadsheet goes to the wrong list. A professional-services firm wants project managers to see hours and deadlines by consultant, but not each consultant’s charge-out rate or salary. Without column rules the firm either builds two copies of every report or trusts people not to scroll right. A clinic has the same problem with patient names on operational dashboards: managers need counts and waiting times, not identities.
Column rules are the partner of row-level security, which limits which records a person sees. Rows answer “which customers”; columns answer “which facts about them”. Most teams need both, and the rule of thumb is that a permission that only applies on the dashboard is not a permission: it has to hold in downloads, scheduled reports, embedded views and AI answers too, or someone will find the side door.
In Klayara, column rules are set once per role or person and applied everywhere the data appears — dashboards, downloads, scheduled reports, embedded views and AI chat — with an activity log of every change. See security and permissions.