MailerSend Email Tracking: What It Sees and How to Block It

MailerSend email tracking is not hidden, exactly. It is described in the vendor's help pages in language most recipients will never read, controlled by a toggle only the sender can see, and routed through a host called click.mailersend.net that identifies the platform to anyone who thinks to look at a link before following it. Because MailerSend is a transactional platform first, this is tracking attached to mail you asked for rather than mail you signed up for, which is a different problem than a newsletter pixel. Everything below comes from MailerSend's published docs plus DNS lookups run on 19 August 2026.

Key Takeaways

• MailerSend's documentation defines open tracking as "an invisible beacon embedded in your emails" that "lets you see who has opened your emails", enabled or disabled per domain by the sender.
• Click tracking rewrites links to the shape unique-subdomain.click.mailersend.net/unique-id-for-unique-link, and MailerSend states it "automatically replaces all links in HTML and TEXT content that is sent via the MailerSend API".
• A DNS lookup on 19 August 2026 shows *.click.mailersend.net is a wildcard answering on any subdomain, resolving to Cloudflare addresses 104.18.35.108 and 172.64.152.148, while sibling names such as open.mailersend.net do not resolve at all.
• MailerSend's analytics API exposes /v1/analytics/country, /v1/analytics/ua-name for "browser and operating system", and /v1/analytics/ua-type for "the reading environment (webmail, mobile, desktop)".
• The domain mailersend.net was registered on 9 April 2020 through NameCheap behind the privacy service Withheld for Privacy ehf.

What Is MailerSend?

MailerSend is the transactional email arm of MailerLite, built for the mail software sends automatically: order confirmations, verification codes, invoices, alerts.

That focus matters for how you should read the rest of this. A newsletter is something you subscribed to and can leave. A password reset is something you triggered by trying to get into your own account, and there is no unsubscribe from it. Applying one measurement layer to both quietly voids the consent story marketing email leans on.

MailerSend does not treat transactional mail as exempt. Its domain tracking options documentation presents open tracking, click tracking and content tracking as domain wide switches, and its send email API reference exposes the same three as a per message settings object containing "track_clicks, track_opens and track_content and a boolean value of true or false". Compare that to Loops, which never tracks transactional mail at all, and the difference is a design decision rather than a technical necessity.

What Does MailerSend Actually Record?

Your open, your click, the country your request came from, and the browser, operating system and reading environment your mail client reported.

MailerSend's own wording on opens is direct: an "invisible beacon embedded in your emails lets you see who has opened your emails." On clicks it is more specific still, promising the sender "all click activity, including which links are clicked, how many times each link was clicked, and which recipient clicked." Not counts. Which recipient.

The MailerSend analytics API shows how far the derived data goes. Three endpoints exist purely to slice opens: /v1/analytics/country groups by country, /v1/analytics/ua-name groups "by user agent name (browser and operating system)", and /v1/analytics/ua-type groups by "the reading environment (webmail, mobile, desktop)". None of that is transmitted by you deliberately. Country is inferred from the IP address that fetched the beacon, and browser and platform come from the user agent string your client attaches to any image request.

On the event side, the activity API lists the recorded types explicitly: queued, sent, delivered, soft_bounced, hard_bounced, deferred, opened, opened_unique, clicked, clicked_unique, unsubscribed, spam_complaints, survey_opened, survey_submitted, suppressed. The pairing of opened with opened_unique tells you something on its own. A system that distinguishes total opens from unique opens is counting repeat views by the same person, which means the record is keyed to you and persists.

What Is click.mailersend.net?

It is the shared host every MailerSend link redirect passes through unless the sender configured a branded alternative on their own domain.

MailerSend documents the default link shape as unique-subdomain.click.mailersend.net/unique-id-for-unique-link, where the leading label identifies the sending account. Senders who enable the custom DNS records for tracking option instead point a CNAME at MailerSend, and the docs suggest email.yourdomain.tld, producing links on the sender's own name. This is the same pattern Resend uses when it rewrites links through the sender's subdomain, and it is marketed as a deliverability improvement. For a recipient it is camouflage, because the redirect is no longer recognisable as a third party.

DNS confirms the default arrangement. On 19 August 2026, invented names such as gblocktest.click.mailersend.net and test.click.mailersend.net both resolve to 104.18.35.108 and 172.64.152.148, Cloudflare addresses, and a request to an invalid path returns HTTP 404 with an x-envoy-upstream-service-time header, so a live application is answering rather than a static bucket. A wildcard is exactly what a per account subdomain scheme requires. Meanwhile open.mailersend.net, track.mailersend.net and pixel.mailersend.net return nothing, which means the wildcard is scoped to click and not to the zone as a whole. From the registry, mailersend.net was created on 9 April 2020 through NameCheap, registrant hidden behind Withheld for Privacy ehf.

One honest gap: MailerSend does not publish the hostname that serves the open beacon, and we did not find it documented anywhere. It plausibly rides the same tracking subdomain as clicks, since that is what the shared CNAME setup implies, but we have not verified that and will not assert it. Check a real message rather than trusting a guess, including ours.

How Do You See the Pixel Yourself?

Open the raw message source in Gmail and read the HTML, which takes about thirty seconds and settles the question for that specific sender.

Use the three dot menu on the message, choose Show original, then search the source for click.mailersend.net. Any hit in an href means click tracking is on for that domain. Then look for an img tag with a width and height of 1, or a src pointing at a host that has nothing to do with the sender's product. MailerSend's docs note the beacon can be placed either just before the opening body tag or at the bottom of the message, so check both ends. Our walkthrough on detecting email tracking pixels in Gmail covers the same method for platforms that hide it better.

If a sender has set up custom DNS records for tracking, you will see their own subdomain instead. A link on email.example.com that lands on example.com after a redirect is doing the same job with better manners.

How Do You Block MailerSend Tracking in Gmail?

The open is an image request and the click is a redirect, so both are interruptible in the browser, though the branded domain option makes blanket rules less reliable here than on single host platforms.

• Stop images loading automatically. Gmail Settings, then General, then "Ask before displaying external images", documented on Google's images settings help page. The beacon never fires, so no open event is created. It also blocks images you wanted, and does nothing about clicks.
• Block the tracking host. A rule covering click.mailersend.net and its subdomains handles every sender still on the default. Gblock removes tracking pixels inside Gmail before the request leaves your browser.
• Do not follow the rewritten link. Each MailerSend link carries a unique id tied to your address, so the click is attributed the moment you tap it. Navigate to the destination from the sender's site, or let Gblock strip the redirect so the real URL opens directly.
• Watch for branded tracking domains. When a sender uses email.theirdomain.com, no platform wide rule catches it, which is why a maintained blocklist beats a rule you wrote once and forgot.
• Know the limits. Delivery, bounces, unsubscribes and spam complaints are logged server side. Blocking removes the open and the click, not your row in the sender's contact list.

How Does Gblock Compare to Ugly Email, PixelBlock and Trocker?

All of them block pixels; they differ in whether tracked links are handled and whether the list keeps up on its own. We go through the trade offs in our roundup of the best email tracker blocker extensions.

Ugly Email is MIT licensed, flags tracked Gmail threads with an eye icon and blocks the pixel locally. Trocker is free and open source, spans several webmail providers, and is the one free tool that also marks tracked links. PixelBlock does straightforward pixel blocking, though its Manifest V2 lineage means you should check you have a maintained build. Proton Mail and HEY bake protection into the client, which is genuinely strong and genuinely irrelevant if your mail lives in Gmail.

Gblock's claim is narrow rather than superior. It works inside Gmail instead of asking you to change providers, it strips tracking links as well as pixels, and its blocklist updates itself, which matters more for a platform like this one than for a single host vendor. The same reasoning applies to Mailmeteor and other Gmail based senders.

Why Email Users Should Care

Most coverage of email tracking is about marketing lists, and that framing lets transactional platforms off a hook they should be on. You can leave a newsletter. You cannot decline the receipt for something you bought, and MailerSend's switches sit with the sender either way.

Think about what an open record on transactional mail actually reveals. A shipping notification opened at 02:14 from a mobile reading environment in a country the account has never ordered from is a timestamped location signal attached to a real name, generated by a message nobody would think of as marketing. Multiply that by a normal week of receipts, alerts and verification codes and the log becomes a rough movement history, built without any deliberate act beyond opening your mail. The reading environment endpoint exists specifically to make that dimension queryable.

There is a compliance angle too, and it is not settled. France’s CNIL, in its April 2026 recommendation on email tracking pixels, and Italy’s Garante both treat an open pixel as a form of terminal access that generally needs prior consent, because the pixel is not necessary to deliver the service you requested. A sender who leaves the domain wide toggle on has made that call for every recipient at once, usually without noticing there was a call to make.

The Honest Summary

MailerSend documents what it does in plain terms, gives senders both a domain level switch and a per message settings object, and does not pretend the beacon is anything other than a beacon. Credit where it is due.

What it does not do is carve out transactional mail, and that is the whole product. The result is open and click records on messages you never opted into, on a wildcard host registered behind a privacy service in 2020, with the choice resting entirely with the party doing the counting. Your mail client fetching an image is the only step in that chain on your side of the wire. It is also the only one you control.