Is that unsubscribe really one-click?
Paste an email’s raw headers and this page tells you which exit the sender actually gave you: a true RFC 8058 one-click, a link to a page, a mailto:, or nothing at all.
Everything runs in your browser. Your paste is never uploaded — check the network tab. The parser is a static JavaScript file; no request this page makes ever carries your text, and nothing you paste is stored or logged. The page does load the site’s standard page-view analytics — they count the visit, never see the paste.
Paste your raw headers above, then press Analyze. Nothing leaves this page.
The four answers
List-Unsubscribe-Post plus an https target. One machine request submits the opt-out; sender processing is a separate outcome. Machine clicks: 1.List-Unsubscribe header. There is no standard header route; verified account settings, a trusted footer link, or provider controls may still exist.Find your headers
Gmail
Open the message, click the ⋮ menu at the top right of the email, then Show original. Copy everything from the new tab — the headers are the block at the top, above the first blank line.
Apple Mail (macOS)
Select the message, then View → Message → All Headers (or press ⇧⌘H). Copy the header block that appears above the message body.
Outlook (desktop)
Open the message in its own window, then File → Properties. The header block sits in the Internet headers box at the bottom — select it all and copy.
Don’t trim anything — pasting the whole “Show original” page (Gmail: ⋮ → Show original → select all) is fine. The checker finds the header block on its own and never reads past it into the body.
Questions
What is a one-click unsubscribe?
RFC 8058 one-click needs two things in the email: a List-Unsubscribe header with an https target, and a List-Unsubscribe-Post: List-Unsubscribe=One-Click header. Together they let your mail client send one machine request without a web page or login. Google requires that method for covered subscription and marketing mail from senders of more than 5,000 messages a day to personal Gmail accounts. Yahoo publishes no matching numeric threshold; it requires bulk senders to provide a functioning List-Unsubscribe header, highly recommends RFC 8058 POST, and accepts mailto.
Why is a mailto: unsubscribe weaker than an https one?
A mailto: exit asks the mail client to send an email request. RFC 8058 instead defines a machine-readable HTTPS POST that a provider can trigger without opening a sender page. Either route still depends on the sender applying suppression; this checker identifies the advertised mechanism and does not prove that later mail stops.
Does this tool upload my email anywhere?
No. The parser runs entirely in your browser as a static JavaScript module, and the page makes no network calls with your text. Nothing is sent, stored or logged — open your browser’s network tab and press Analyze to confirm it yourself.
An https link is present, so why does it say "not one-click"?
Because a link is a page, not a promise. Without the List-Unsubscribe-Post header nothing can unsubscribe you automatically; the link opens a page, and that page can ask for a login, fifteen toggles, or a confirmation you never finish. The gap between those two exits is exactly what the Exit Gap Index measures.
Where this comes from
This checker runs the same parser the Exit Gap Index uses to read the advertised machine path. Google requires senders above its personal-Gmail threshold to support RFC 8058 on covered marketing and subscribed mail; other messages may expose a different route or none. The Index measures what happens next only after its evidence gate is met: the human path a person actually walks.
Want to feel that maze rather than read about it? Play the Unsubscribe Museum.
Found a sender whose exit deserves a grade? Tell us: hey@flicked.email.
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