All blogs & guides

TRACKING & CONTENT

Open Tracking, Link Tracking, and HTML: Are They Hurting Your Deliverability?

By TransmitInbox team
Published August 21, 2026 · Updated October 11, 2026

You’re told to turn off tracking and switch to plain text because the campaign isn’t getting replies. Those changes are worth testing, but they won’t tell you the cause on their own. First look at what the sending tool actually adds to the received message.

Open tracking measures image loads, not confirmed reading

For European campaigns, review tracking and personal-data use alongside the applicable privacy and electronic-marketing rules; permission to send doesn’t automatically settle tracking. Keep US, Canadian, and European test groups separate when settings differ. A tracking-free comparison should use eligible recipients, comparable messages, and human replies—not a claim that removing pixels guarantees inbox placement. Test the received tracking link too: check its certificate, redirects, and availability.

Open tracking usually works by adding a tiny invisible image to an HTML email. When that image downloads, the sending platform records an open. If the recipient’s email client blocks images, someone can read your message without generating that event (see Mailchimp’s open-tracking documentation).

The opposite can also happen. Apple’s Mail Privacy Protection can download remote content in the background regardless of whether the recipient engages with the message. A recorded image load therefore doesn’t necessarily mean someone read your email. Apple’s privacy documentation describes this behavior.

That makes ‘opened but didn’t reply’ a shaky basis for another message. Some people in that segment may never have read it, while somebody in ‘never opened’ may already have seen the offer.

Google also says it doesn’t track open rates and can’t verify third-party open-rate accuracy. Low reported opens alone aren’t a reliable indicator of delivery or spam classification. Google’s sender guidelines make that distinction explicit.

Switching tracking off removes a measurement mechanism. It doesn’t prove the pixel was responsible for the delivery problem. If the reports are what’s confusing you, the open-rate guide covers how to interpret them before changing the campaign.

Link tracking adds another step to the recipient’s journey

Click tracking commonly replaces your destination URL with a tracking URL. The recipient clicks that address, the tracking service records the event, and then redirects them to the intended page. Mailchimp’s click-tracking documentation explains this process.

Check the actual message received in a test mailbox:

• Does the link lead to the intended page?
• Is every step using a working HTTPS connection?
• Does the destination match what the anchor text promises?
• Does the link work on both desktop and mobile?

A branded tracking domain can look more familiar. Still check where it leads and how it’s configured; the name alone won’t tell you the connection or reputation is healthy.

Also, disabling click reporting may not remove every redirect. Some platforms continue rewriting links for other purposes; Mailchimp documents circumstances where this happens. Inspect the received link instead of assuming a dashboard toggle changed it.

Finally, clicks aren’t always human. Security tools can visit links automatically, inflating reports. Mailchimp’s bot-activity guidance explains why click totals need interpretation.

HTML itself is not a reason to abandon your template

HTML allows formatting, images, buttons, and structured layouts. Google’s guidelines explicitly address HTML messages and require them to follow HTML standards. They also call for understandable links and discourage hidden content. These requirements don’t support a blanket claim that all HTML email belongs in spam (see Google’s sender guidelines).

Start with an introduction that still makes sense if the decorative parts don’t load. Who’s writing, what are they offering, and what are they asking the recipient to do? If those answers depend on an image, simplify the message.

A practical template can use:

• Short paragraphs with readable text.
• A simple signature that identifies the sender.
• Descriptive links where they serve a clear purpose.
• Essential information written as text rather than embedded in an image.

A newsletter layout may be unnecessary for a short introduction. Check it on the clients your test accounts use, including with images unavailable. Extra layout code gives you more to inspect, and a message built around pictures can lose its meaning when they don’t appear.

Use the images and links the message needs, then test them. There isn’t a fixed count that guarantees inbox placement.

An email can look like plain text and still contain HTML or a tracking pixel. Ask how the platform builds it, or inspect the received source. What you see on screen doesn’t reveal every component.

Test one change at a time

If you turn off tracking, rewrite the message, replace the links, and lower volume together, you may see a change. You’ll also be left wondering which change mattered.

Start with controlled test mailboxes you can inspect. Keep the sender, subject, wording, and destination consistent while changing one component:

1. Compare the same HTML message with and without open tracking.
2. Compare a tracked link with a direct link to the same page.
3. Compare simple HTML with a plain-text version carrying equivalent information.

Check the folder result, rendering, authentication, and links in the test accounts. That tells you about those messages in those mailboxes; it doesn’t predict what every recipient will see.

For a limited campaign comparison, keep the audience groups and timing as comparable as possible. Note the conditions. A better group of contacts or a different sending schedule can otherwise look like an improvement caused by the tracking change.

Choose results you can still observe with tracking disabled: failures, real replies, qualified conversations, and relevant conversions. Comparing open rates won’t help if one version has no way to record an open.

Keep the required unsubscribe options working. If the problem survives several versions, look at the wider causes of spam placement rather than spend another round toggling template settings.

Quick checklist before your next campaign

Before deciding that tracking or HTML is the culprit:

• Inspect a received email, including its actual link destinations.
• Confirm the message is readable with images blocked.
• Test redirects and landing pages on desktop and mobile.
• Treat opens and clicks as imperfect signals of human activity.
• Change one variable and document the result.
• Preserve sender identification and unsubscribe functionality.
• Check delivery errors and recipient feedback alongside campaign reports.

Pause before expanding just because the reported open rate rose. A change in how the tool measures events can improve the chart without improving delivery or people’s interest.

Check the additions your tool makes before blaming tracking or HTML as a whole. TransmitInbox’s managed service can help inspect the message and link setup, then choose a test that answers the question you’re actually trying to resolve.