SCIM Provisioning for Email Signatures

SCIM, the System for Cross-domain Identity Management, is the standard protocol identity providers use to keep downstream applications in sync with their user directory. Instead of the application repeatedly asking the directory who exists, the identity provider pushes create, update, and deactivate events as they happen. For email signatures this changes the timing of two events that matter. A new hire gets a correct signature from their first outbound email rather than at the next sync interval, which for a client-facing role is the difference between a professional first impression and a blank block. And a leaver's signature stops being applied at deactivation, which matters because a departed employee's mailbox is often kept alive for forwarding and continues to send. SCIM is distinct from directory sync in the general sense. Directory sync usually describes reading Google Workspace or Microsoft 365 on a schedule; SCIM describes the identity provider pushing changes in real time and is typically associated with Entra ID, Okta, or a similar IdP sitting above the mail platform. Organizations without a separate identity provider generally do not need it, since reading the mail directory directly covers the same ground.