Is Lemlist Tracking Your Email? How to Block It

You didn't ask to receive this email. You didn't sign up for anything. But the moment you open it, a sales team somewhere is watching — they know you read it, when you read it, what device you used, and roughly where you are. That is how email tracking software works, and Lemlist is one of the most capable email tracker for Gmail and cold outreach platforms doing it at scale today.

Lemlist serves over 10,000 customers — mostly B2B sales teams running cold outreach at volume. If you work in a role that attracts sales attention (finance, IT, operations, leadership), there is a real chance some of your unread messages carry Lemlist's tracking infrastructure inside them, waiting for you to open them.

Key Takeaways

• Lemlist embeds an invisible 1×1 pixel in HTML emails that fires silently when you open the message, logging the open timestamp, device type, IP address, and email client.
• Lemlist now requires a Custom Tracking Domain before enabling tracking — meaning clicks route through a sender controlled subdomain like trail.yourdomain.com, not lemlist.com directly.
• Because Lemlist's click tracking uses custom domains per sender, static blocklists that only block lemlist.com may miss Lemlist tracking entirely.
• Recipients have no in-tool opt-out — the tracking is configured by the sender and recipients cannot disable it within Lemlist's interface.
• Gblock uses AI detection to identify Lemlist tracking pixels and custom tracking domains, not just static domain lists, which is why it catches Lemlist even when senders use custom subdomains.

What Is Lemlist?

Lemlist is an AI-powered cold outreach and sales engagement platform founded in Paris in 2018. It gives sales and growth teams a full stack for cold email campaigns: lead discovery from a 600M+ contact database, AI personalization that customizes each email at scale, multichannel sequences across email, LinkedIn, and calls, and built-in email warm-up to improve deliverability. By 2025, Lemlist reported $40M in annual recurring revenue and over 10,000 active customers.

What makes Lemlist different from simpler email tools is that tracking is not an add-on — it is the product's engine. Sales teams use open and click data to decide who to follow up with, when, and how aggressively. Sending without tracking in Lemlist is like flying blind.

Does Lemlist Track Email Opens?

Yes. Lemlist embeds a transparent 1×1 pixel image in every tracked HTML email. When your email client renders the message and loads images, it fetches that pixel from Lemlist's tracking servers. That fetch is an HTTP request — it carries your IP address, the exact timestamp, your device type, and your email client as standard metadata.

Lemlist's server receives the request, logs it, and pushes a notification to the sender's dashboard. The sender sees: you opened the email, at what exact time, on a mobile device, in a particular city. If you open the email again, each open is logged separately, building a behavioral timeline. According to Lemlist's own help documentation, open tracking is enabled by default on all campaigns until a sender manually disables it in Settings.

Gmail's image proxy partially mitigates this: Google routes image loads through its own servers, so Lemlist sees Google's IP instead of yours. But that partial protection disappears the moment you click a link.

Does Lemlist Track Link Clicks?

Yes, and this is where Lemlist's tracking goes further. Every link inside a Lemlist email is rewritten before sending. Instead of pointing directly to the destination URL, it routes through a tracking redirect first. When you click, your browser hits that redirect server, which logs your IP address, the timestamp, your device, and which specific link you clicked — then forwards you to the actual destination.

This click tracking happens completely outside Gmail's image proxy. Your real IP address goes directly to Lemlist's tracking infrastructure on every click, regardless of your image loading settings.

According to Lemlist's help center, click tracking is considered core campaign intelligence — it tells senders not just that you read the email, but which offer or link caught your attention. That is a materially richer data point than an open event alone.

Why Custom Tracking Domains Make Lemlist Harder to Block

This is the detail most recipients — and many privacy tools — miss.

Lemlist now requires a Custom Tracking Domain (CTD) before senders can enable open or click tracking. If a sender has tracking enabled and no CTD configured, Lemlist blocks the send entirely. What that means in practice: the sender creates a subdomain on their own domain — something like trail.yourdomain.com or track.companyname.com — and points it at Lemlist's servers. When you receive a tracked email, the pixel and all rewritten links use that custom subdomain, not lemlist.com.

The implication for privacy tools is significant. A static blocklist that only knows about lemlist.com or track.lemlist.com will not block a pixel served from trail.yourdomain.com. The request looks like a first-party asset from the sender's domain. To a simple domain-matching blocklist, it is invisible.

What Data Does Lemlist Collect?

Each open event captures:

• IP address — used to infer your city and approximate region
• Timestamp — exact date and time of every open
• Device type — mobile, tablet, or desktop
• Email client — Gmail web, iOS Mail, Outlook, and so on
• Open count — how many times you have opened the same message

Each click event adds:

• Which specific link was clicked
• Click timestamp
• IP address at click time — your real IP, not Google's proxy

This is not anonymous aggregate data. It is a timestamped behavioral record tied to your specific email address. A sales rep can see that you opened their email three times over two days, forwarded it (inferred from a second device open), and clicked the pricing link — all without you doing anything visible.

How to Tell If an Email Is From Lemlist

You cannot always tell by looking at the message. Lemlist emails look like ordinary emails. The tracking is in the HTML structure, not the visible content.

To check, open the email in Gmail and select "Show original" from the three-dot menu. In the raw HTML source, search for:

• lemlist — appears in unobfuscated pixel URLs and some header metadata
• trail. or track. subdomain patterns in link hrefs — common CTD prefixes
• A 1×1 image tag appearing after all visible content, pointing to an external domain

The link rewriting is the more reliable signal. Every link in a Lemlist email is a redirect URL, never a direct destination. If you hover over a link and the href shows a domain different from where you expect to land, that is click tracking. For a broader method that works across multiple tracking tools, the email open tracking vs click tracking guide explains what to look for in raw headers.

How to Block Lemlist Tracking in Gmail

Three approaches exist, in order of effectiveness:

1. Disable image loading. In Gmail, go to Settings → General → Images → "Ask before displaying external images." This stops open tracking pixels from firing. It does not stop click tracking, and it degrades the experience for every email, including legitimate ones you want to display normally.

2. Plain text mode. Forcing all emails to plain text strips HTML entirely, including all tracking pixels and rewritten links. Complete protection, but most people find it too disruptive.

3. Gblock. Gblock is a Gmail extension built specifically for this problem. It automatically detects and blocks tracking pixels before they fire — including Lemlist's. The critical differentiator for Lemlist specifically is how Gblock handles the custom domain problem: instead of relying only on a static list of known Lemlist domains, Gblock uses AI to identify tracking patterns, including pixels and redirect links served from custom subdomains. A sender using trail.theircompany.com doesn't slip through because Gblock is not solely matching against lemlist.com.

You keep images enabled for newsletters and legitimate senders. Gblock is surgical about what it blocks. The tracking signals never reach Lemlist's servers. For a comparison of blocking approaches across multiple sales tools, see how to block email tracking in Gmail.

Lemlist is a well-built product that does exactly what it promises. The problem is not the sender's dashboard — it is that you, the recipient, are on the other side of that dashboard without having agreed to be. Cold outreach means you likely never asked to receive these emails in the first place. The custom domain requirement makes Lemlist's tracking harder to block than most tools in this category. Pattern-based detection, not static domain lists, is how you stop it reliably.