Custom Tracking Domain

When you enable open and click tracking in your cold email platform, it rewrites links and adds tracking pixels. By default, these use the platform's domain (e.g., track.instantly.ai). Custom tracking domains use your own domain instead (e.g., link.yourdomain.com). This matters for deliverability because shared tracking domains can be flagged if other users abuse them. A custom tracking domain isolates your reputation and looks more professional. Setup typically involves adding a CNAME record to your DNS that points your subdomain to the platform's tracking server. Most cold email platforms support this on paid plans.