Free tool
One-click unsubscribe header checker
Google and Yahoo require one-click unsubscribe on bulk mail to personal accounts, and the rules are exact enough to get wrong quietly. Paste a sent message's headers and see whether yours actually satisfy RFC 8058.
Runs entirely in your browser. Headers identify your recipient and your sending infrastructure, and none of it is uploaded.
The postal-address check is a heuristic — it looks for common address patterns and will miss plenty of valid international ones. It is a prompt to look, not a compliance verdict.
Oxeyo adds these headers to every send
Both headers and a per-recipient signed token go into every outbound email with nothing to configure. Your postal address is set once in settings, and a campaign will not start without it — so the CAN-SPAM requirement is enforced rather than remembered. An unsubscribe is honoured immediately and suppresses that address across every campaign in your account, not just the one it came from.
See how sending works