Templates & branding
A template is HTML + Mustache fields + optional CSS variable overrides. The brand palette (5 colors, 1 font) sits one level up and is referenced as CSS variables (--primary, --secondary, etc). Drafts don't affect rendered signatures; publishing bumps the template version.
Directory sync
Sync mode: Disabled, Manual, or Automatic. Selection mode: All users, Specific groups, or Specific users. Each run writes a sync_runs row with counts and timestamps so you can audit what changed.
Outlook & Gmail add-ins
The add-ins are thin: they fetch a vendor-signed identity token, POST it to the render endpoint, and insert the returned HTML into the active compose body. They never read the message body, recipients, subject, or thread.
Render API
POST /api/render with the vendor identity token in the Authorization header. The endpoint resolves the user, merges template + global brand + per-user fields, and returns HTML with a short cache window. 401 on invalid token, 404 on unmapped user.