Is Mailjet Tracking Your Email? How to Block It

You open a shipping notification or a newsletter and think nothing more of it. But if the company behind that email uses Mailjet, the platform can already know you opened it, what time you did, and which country you opened it from. Mailjet email tracking is not hidden or unusual. It is a standard feature built into one of the largest transactional and marketing email platforms on the internet, sitting behind messages from stores, apps, and services you use every week. Here is what Mailjet's own documentation says about how open tracking and click tracking actually work, what gets stored about you, and how to stop it inside Gmail.

Key Takeaways

• Mailjet's help documentation confirms that once open tracking is switched on, an invisible tracking pixel is added to every email a sender pushes through the platform, the same 1x1 image mechanic used across the email marketing industry.
• Mailjet rewrites every clicked link to route through its own mjt.lu domain by default, in a format like https://os8n.mjt.lu/redirect/12345/hostname/link, before forwarding your browser to the real destination.
• Mailjet's Event Tracking API logs the IP address and country code behind every open and click event, tied to that specific recipient, and makes that data available to senders in near real time.
• Sinch acquired Mailjet's parent company, Pathwire, for 1.9 billion dollars in a deal that closed in December 2021, folding Mailjet into a much larger cloud communications business alongside Mailgun.
• Gblock blocks Mailjet's tracking pixel before it loads in Gmail, the same way it already blocks tracking from SendGrid, Brevo, and the other email platforms covered in this series.

Does Mailjet Track Email Opens?

Yes, once a sender switches open tracking on in their Mailjet account. Per Mailjet's own glossary entry on tracking pixels, a tracking pixel embedded in an email "tracks recipients when they open a message," and Mailjet's help documentation on email statuses confirms that an invisible pixel image gets added to every message sent through the platform once the feature is activated in account preferences. That is a meaningful detail: open tracking sits behind an account level toggle rather than being permanently welded on, which puts Mailjet closer to a default that senders can turn off than a hard coded requirement.

In practice, most senders leave it on, because open rate is one of the core metrics email marketing teams report to their managers. Mailjet's Send API also exposes a per message TrackOpens parameter that accepts account_default, enabled, or disabled, letting a developer override the account setting for an individual campaign or transactional send. Mailjet is honest about the limits of what that pixel actually proves, too: its own documentation notes that opens go unrecorded when a recipient blocks images, reads in plain text, or uses a client running its own privacy protections, all of which quietly inflate or deflate the numbers a sender sees on their dashboard.

How Does Mailjet Click Tracking Work?

Mailjet rewrites every clickable link in a tracked email so it routes through Mailjet's own infrastructure first. Per Mailjet's help center article on customizing tracking links, the default rewritten link looks something like https://os8n.mjt.lu/redirect/12345/hostname/link, with a subdomain and numeric identifier unique to the sending account. Click the link and Mailjet's server logs the click, attributes it to your recipient record, and only then redirects your browser to the page the sender actually meant to send you to.

Senders can swap that generic mjt.lu domain for their own branded subdomain by pointing a CNAME record at Mailjet, which is why some tracked links look like they belong to the company that sent them rather than to Mailjet at all. There is also a documented escape hatch: adding a NOTRACK attribute to a specific link tells Mailjet to leave that one URL alone even when click tracking is enabled for the rest of the message. That option exists for senders, not recipients, so it does nothing to protect you unless the company emailing you happens to use it. We cover this same redirect through pattern, used by dozens of platforms beyond Mailjet, in our guide to how tracking pixels have evolved to dodge Gmail's defenses.

What Data Does Mailjet Store About You?

Mailjet's Event Tracking API logs the IP address behind every open and click, along with the country code that address maps to, and pushes that data to the sender in near real time through webhooks. Per Mailjet's documentation on the Event Tracking API, that IP can be either IPv4 or IPv6, and it is captured per event rather than as an anonymous aggregate. Mailjet's Campaign Stats dashboard then rolls that up into geographic breakdowns, showing a sender which countries their opens and clicks came from, and its statistics API lets a sender pull the open and click history for a specific recipient on demand.

None of this is hidden or unusual for an email service provider. It is the same category of data Mailjet's competitors collect, and we found close to identical mechanics when we researched Brevo's email tracking behavior. The pattern matters more than any single platform: Mailjet, Brevo, and SendGrid are three of the largest email delivery providers on the internet, and all three log opens, clicks, IP addresses, and geography by design. That is not a bug in one company's product. It is how the entire transactional and marketing email industry is built.

Why Email Users Should Care

Mailjet is not spyware and it is not trying to trick anyone. It is infrastructure, and most people have no idea it sits behind a huge share of the receipts, alerts, and newsletters landing in their inbox every day. Because Sinch's Pathwire acquisition folded Mailjet in alongside Mailgun, the same corporate umbrella now touches a striking share of transactional email traffic across ecommerce, SaaS, and marketing tools, which means the odds that today's shipping confirmation or password reset carries a Mailjet pixel are higher than most recipients would guess.

That is precisely why generic security tools miss it. Antivirus software and spam filters exist to catch malware and phishing, not a legitimate email provider quietly confirming to a sender's dashboard that you opened their message at 8:14 a.m. from a Gmail account in a specific country. A dedicated email tracker blocker for Gmail does not need to judge whether Mailjet or its customers are doing anything wrong. It just keeps the pixel from loading and the rewritten link from phoning home first, closing the same gap for Mailjet that it closes for every other platform running this playbook.

How Do You Block Mailjet Email Tracking in Gmail?

A few approaches work, each with real tradeoffs.

Disable automatic image loading. In Gmail, go to Settings, then General, then Images, and choose "Ask before displaying external images." Nothing loads without your say so, which stops most pixels cold, but it also hides every legitimate image in your inbox until you approve it, which gets old fast once you are past a handful of emails a day.

Hover before you click. Hovering over a link before clicking reveals the mjt.lu rewrite, or a branded CNAME variant, in your browser's status bar, confirming the click is tracked. It does nothing about the open pixel, and it only works if you remember to check every single time.

Use a dedicated blocker built for this. Gblock runs inside Gmail and intercepts tracking pixel requests before they load, including the infrastructure Mailjet relies on for open tracking, without hiding legitimate images or breaking the rest of your inbox. Its blocklist updates automatically instead of shipping as a fixed, manually maintained list, so it is built to keep pace as email platforms rotate through new tracking domains and branded CNAMEs. It also strips known tracking parameters from links, not just pixels, closing the gap that click rewriting otherwise leaves wide open.

How Does Gblock Compare to Ugly Email, PixelBlock, and Proton's Approach?

It is worth naming the alternatives honestly rather than pretending Gblock is the only option. Ugly Email and PixelBlock were early, genuinely useful browser extensions for flagging tracked messages inside Gmail, but both lean on static, manually curated domain lists that struggle to keep up as platforms like Mailjet let senders route tracking through custom branded subdomains instead of a single predictable domain. Proton Mail and HEY take a different path entirely: rather than blocking pixels inside Gmail, they proxy every remote image through their own servers before it reaches you, which hides your IP from senders but requires abandoning Gmail as your email client altogether.

Gblock's focus is narrower on purpose. It stays inside Gmail rather than asking you to switch providers, updates its detection automatically instead of waiting on a manual release, and strips both pixels and tracking parameters in links rather than only flagging a message after the fact. That does not make it a defense against every tracking method that exists anywhere. It does mean the specific mechanism Mailjet relies on, a pixel that loads automatically and a link that redirects through mjt.lu first, never gets the chance to fire in the first place.

A Note for Mailjet Senders: What About Consent?

If you send email through Mailjet rather than receive it, the consent question deserves a straight answer. Per Mailjet's documentation on data protection, Mailjet acts as a data processor, while the business sending the email is the data controller, meaning the legal responsibility for collecting and documenting recipient consent sits with the sender, not with Mailjet itself.

That responsibility has gotten sharper. French and Italian data protection regulators, the CNIL and the Garante, published fresh guidance on tracking pixels under the ePrivacy Directive and GDPR, and Mailjet's own blog post on the guidance summarizes the shift as a mandate to "justify tracking, limit it, and in many cases, get consent for it," because a pixel accessing information from a recipient's device now falls under the same consent framework as a cookie banner. Any Mailjet customer still treating open tracking as an invisible, consequence free default has homework to do before their next campaign.

The Bottom Line

Mailjet is the third major email service provider covered in this series, after SendGrid and Brevo, and the pattern keeps repeating: a hidden pixel for opens, a rewritten link for clicks, and per recipient logging that ties both back to your identity. Three of the biggest names in transactional and marketing email running the same playbook is not a coincidence. It is the default architecture of the industry, and it means blocking the mechanism, not chasing individual companies, is what actually protects your inbox.