How signals are counted

Open detected means MailSignal received an image request that was not classified as automated, a scanner, a preview, or the sender. Image blocking hides opens. Caching hides repeats. Proxies and prefetch can create requests without a person reading the message.

A click is a request to a tracking link. Filtered click counts leave out suspected scanners, prefetch, and automation. The destination is opened with a redirect even when the event is filtered.

Document views count when the hosted viewer renders a page in a visible tab. Downloading a file does not mean it was opened or read. Revoking access does not erase copies already downloaded.

Location is an approximate network location when a geolocation source returns one and the address does not look like a proxy, relay, or hosting provider. It is never GPS. Mail and privacy proxy addresses are labeled Proxy location and are not shown as the recipient.

Gmail accepting a send means Gmail took the message for delivery. It does not mean a recipient's mailbox accepted it or that anyone saw it.

Classification is a heuristic. Unrecognized clients stay Unknown and are excluded from filtered engagement. Gmail's image proxy is labeled as a proxy: it can count as an observed open, and its network location is never shown as the recipient's location. Apple and other privacy relays are excluded when the geolocation source identifies them. Relays that are not labeled can be missed.

Requests in the first 10 seconds after send are treated as possible previews. A person who opens that quickly can be missed. Duplicate requests from the same network hash within two seconds do not increase the filtered count. Without a trusted client IP, that duplicate check cannot run.

MailSignal does not use device fingerprinting, browser geolocation, or a precise map pin.