Best Email Tracker with Confidence Scoring

Each open gets one grade and a reason. Verified: the person replied on the thread, so it's counted. Most likely human: for example opened in Gmail or opened in Outlook desktop, counted. Possibly human: shown with its reason but not counted. A named machine (Apple Mail prefetch, link preview, security scanner) or your own open: shown with the reason, never counted. The grades are fixed steps, not a sliding gauge, and each open shows a grade and why, never a score. If you question one, Diagnose also shows how often that rule has been right lately.

Apple publishes the address ranges its Mail Privacy Protection relays use, and the list changes over time. Outsolvi refreshes Apple's list daily and Yahoo's proxy list weekly, and checks every open against them.

Nobody publishes a figure we'd trust, and we don't have one we'd stand behind for Outsolvi either. The most common miss runs the other way: a human reading immediately on a mobile device through Apple Mail with MPP enabled. The proxy fetches the pixel, the human reads the cached content, and the tracker sees only the proxy fetch, so Outsolvi labels it Apple Mail and doesn't count it. The cleanest signal recovery for this case is the click or the reply, since click tracking does not route through the image proxy, and a click or reply from that person still counts.

Microsoft's 2-tier framework (verified vs preview) prioritizes simplicity for the enterprise reporting use case where executives want a clean number. Outsolvi's grades (verified, most likely human, possibly human, and the named machine kinds) prioritize showing the rep why, which helps in the middle band where an open could go either way. Both approaches are defensible, the tradeoff is dashboard simplicity versus seeing the reason behind each open.

Adding it as a post-hoc analytics layer is straightforward (Yesware does this, known-bot detection). Adding it at the HTTP request level requires re-architecting how pixels are served and classified, which is a larger engineering investment. Outsolvi was built with open grading as a primary feature. Retrofitting it to a 2010s-era tracker is non-trivial.

Click tracking is structurally less affected by Apple MPP, because Apple's privacy proxy fetches images, not links. Security scanners are a different story: they follow links to check them, and at large corporate domains they can account for most clicks. Click rate has become the cleaner single signal in 2026 for the first reason, it survives Apple MPP almost entirely, as long as scanner clicks are filtered out. Outsolvi grades clicks too: a click from a known scanner, from a script rather than a browser, or within half a second of an open from the same address is recorded and labelled but not counted, and link previews from apps like Slack, LinkedIn or WhatsApp get their own label.