How open & click tracking works

RadarSend measures who opens your emails and who clicks your links, then filters out the automated “opens” and “clicks” that machines generate so your numbers reflect real people. This guide explains how the tracking works and — importantly — why your open and click rates may look lower here than in a tool that counts everything.

How opens are tracked#

Every email RadarSend sends includes a tiny, invisible tracking image (often called a “pixel”). When someone opens your email and their mail app loads that image, RadarSend records an open.

That image is served from your tracking domain — a branded subdomain on your own domain, like track.acme.com. Open and click tracking don’t work until your tracking domain is live, so this is a required setup step. See Set up your tracking domain.

A couple of things worth knowing:

• A click also counts as an open. If someone clicks a link without their mail app ever loading the pixel, RadarSend still credits them with an open.
• Opens are inherently fuzzy. Because opens depend on images loading, they’re the noisiest signal in email — which is exactly why the filtering below matters.

How clicks are tracked#

When RadarSend sends your email, it rewrites the links in it so they route through your tracking domain first. A recipient clicks the link, RadarSend records the click, and then instantly forwards them to the real destination — they just land on the page you linked to, usually without noticing the hop.

This is why links need a live tracking domain too: the same branded subdomain that serves the open pixel also handles click redirects. Using your own subdomain (rather than a shared one) keeps your links on your brand and protects your link reputation.

Why your numbers may look lower than other tools#

This is the big one. If you’ve used another email tool, RadarSend’s open and click numbers may look lower. That’s not a bug — it’s the point.

A large share of “opens” and “clicks” in email aren’t people at all. They’re machines:

• Inbox privacy features like Apple Mail Privacy Protection pre-load images for the recipient, generating an “open” whether or not a human ever looked at the email.
• Image proxies and prefetchers (for example, Gmail routes images through Google’s servers) fetch your pixel automatically, often within seconds of delivery.
• Security scanners at the recipient’s company (Microsoft, Proofpoint, Mimecast, Barracuda, and others) open your email and click every link to check them for threats — before the person has even seen the message.

RadarSend runs a bot classifier that looks at these events and sorts each one into three buckets:

• High (human) — presumed a real person. Counted in your numbers.
• Low (uncertain) — suspicious but ambiguous. Held out of your headline numbers.
• Bot — almost certainly automated. Filtered out entirely.

Bot and uncertain events don’t count toward your open rate, click rate, or engagement/lead scoring. So RadarSend’s rates reflect real human engagement, while a tool that counts every pixel load and every scanner click will report inflated numbers. A lower number here is usually a more honest number.

The classifier re-runs automatically about every 15 minutes, so numbers on a very fresh send can shift slightly as scanning activity gets sorted out.

Reading your engagement numbers#

Open a broadcast to see its results. On the broadcast’s report, the Open rate tile shows two figures:

• The apparent open rate — every recorded open, including bots and inbox previews. This is the “counts everything” number, comparable to what other ESPs report. Its context line reads “total opens · includes bots & previews.”
• A ✓ Verified figure beneath it — the rate after filtering, labelled with the count of real people.

Click rate on the same report is already filtered — it counts verified clicks only.

While a send is still being processed, tiles may briefly show “Reviewing activity — scanners are being filtered” as the classifier does its pass. In the broadcast list, hovering the Open column explains: “machine and scanner opens are filtered out (comparable to other ESPs). A click also counts as an open.”

If you want to see the filtering itself, go to Settings → Deliverability → Bot classifier. It shows a live breakdown — Total events, High (human), Low (uncertain), Bot, and Unclassified — so you can see exactly how much automated noise is being removed.

Common issues#

• No opens or clicks are tracking at all. Almost always the tracking domain isn’t live yet. Check Settings → Developer → Web & tracking domains and confirm the domain shows Live, and that your sender is using it. See Set up your tracking domain.
• My open rate dropped after switching to RadarSend. Expected — you’re now seeing verified human opens instead of inflated totals that included bots and Apple/Gmail image prefetching. Compare against the apparent open rate on the report if you want an apples-to-apples number versus your old tool.
• A specific click didn’t register. Some security setups strip or block tracked links, and some clicks get classified as scanner activity. One missing click among many is normal; a pattern of zero clicks points back to the tracking domain.
• Numbers changed a few minutes after sending. The bot classifier runs about every 15 minutes, so a fresh send’s rates settle slightly as automated events are filtered. This is expected.

Good to know#

• Website tracking sharpens the picture. Turning on website tracking (part of the setup checklist) lets RadarSend confirm that an uncertain click led to a real page visit in a real browser — and promote it back to a genuine human click. Without it, more clicks stay in the “uncertain” bucket.
• The apparent number is never thrown away. RadarSend keeps the full total so you always have a like-for-like comparison against tools that don’t filter — it just doesn’t let bots drive your headline rates.
• Advanced users can tune the filters. The Bot classifier settings page lets you adjust the detection thresholds, but the defaults are tuned for typical audiences — most people never need to touch them.
• A tracking domain is separate from your sending domain. The sending domain authenticates who sends; the tracking domain measures what recipients do.