List-Unsubscribe parser
Per RFC 2369 + RFC 8058, the List-Unsubscribe header carries one or more unsubscribe methods. This tool parses them and tells you which one a sender prefers.
Parsed methods will appear here.
FAQ
What's the difference between RFC 2369 and RFC 8058?
RFC 2369 defined the List-Unsubscribe header (mailto / http). RFC 8058 added the List-Unsubscribe-Post header for one-click unsubscribe via HTTP POST.
Which method should a sender support?
All major mailbox providers in 2024+ require RFC 8058 one-click for bulk senders. mailto and HTTP are still acceptable for fallback.
Why does the order of methods matter?
Receivers prefer HTTP one-click because it doesn't generate outbound mail. mailto is simpler but slower and less reliable.
Is this safe to run on real headers?
Yes. Parsing happens in your browser; no data is sent anywhere.