What is a tracking pixel?

A tracking pixel is a transparent 1×1 image embedded in HTML. When your email client or browser loads it, the sender's server records that you opened the message, along with your IP address, device type, and timestamp — without your knowledge.

Which email clients block tracking pixels?

Apple Mail (with Mail Privacy Protection enabled), Hey.com, and Tutanota block pixels by default. Gmail optionally proxies images. Outlook and most corporate clients do not block them by default.

What third-party domains does this tool flag?

It flags scripts and images from known analytics and ad networks including Google Analytics, Facebook Pixel, Mixpanel, Segment, Hotjar, Intercom, Klaviyo, Mailchimp, SendGrid, and many others.

Is my HTML sent to a server?

No. The HTML is parsed entirely in your browser using the DOMParser API. Nothing you paste is transmitted anywhere.

How do I get the raw HTML of an email?

In Gmail, click the three-dot menu in the top-right of an email and select "Show original" then copy the HTML section. In Apple Mail, go to View → Message → Raw Source. In Outlook, open the email and press Ctrl+U.

Can tracking pixels be hidden in CSS too?

Yes. CSS background images, @import rules, and web fonts can all be used as tracking vectors. This tool scans visible HTML attributes; CSS-based tracking requires a different analysis.

What should I do if tracking pixels are found?

Enable your email client's image blocking or remote content blocking. Use an email provider with built-in tracking protection. Consider using the Strip HTML Tracking tool to remove the elements before forwarding the email.

Does this tool catch all trackers?

No tool can catch all trackers with certainty. Novel domains, obfuscated scripts, and first-party proxied tracking will not be flagged. Use this tool as a quick audit, not a definitive privacy audit.

Privacy Tools /

Tracking pixel detector

Paste raw HTML from an email or webpage to reveal hidden tracking pixels, 1×1 spy images, and third-party analytics scripts embedded in the code.

100% in your browser. Your HTML never leaves your device.

Paste HTML to scan

How to use

Get the raw HTML of an email: in Gmail click ⋮ → Show original, then copy the HTML body.
Paste the HTML into the textarea above.
Click Scan for trackers.
Review the list of suspicious images and scripts detected.
Use Strip HTML Tracking to remove them before forwarding.

Common use cases

Email privacy audit — check newsletters and marketing emails for read receipts.
Web page analysis — copy a page's source and audit third-party scripts loaded.
Before forwarding — scan emails before forwarding to protect the recipient.
Security research — identify unknown tracking domains in HTML you receive.

Also see: Strip HTML Tracking to remove detected trackers, and URL Tracker Cleaner to clean tracking parameters from links.

常見問題

What is a tracking pixel?: A tracking pixel is a transparent 1×1 image embedded in HTML. When your email client or browser loads it, the sender's server records that you opened the message, along with your IP address, device type, and timestamp — without your knowledge.
Which email clients block tracking pixels?: Apple Mail (with Mail Privacy Protection enabled), Hey.com, and Tutanota block pixels by default. Gmail optionally proxies images. Outlook and most corporate clients do not block them by default.
What third-party domains does this tool flag?: It flags scripts and images from known analytics and ad networks including Google Analytics, Facebook Pixel, Mixpanel, Segment, Hotjar, Intercom, Klaviyo, Mailchimp, SendGrid, and many others.
Is my HTML sent to a server?: No. The HTML is parsed entirely in your browser using the DOMParser API. Nothing you paste is transmitted anywhere.
How do I get the raw HTML of an email?: In Gmail, click the three-dot menu in the top-right of an email and select "Show original" then copy the HTML section. In Apple Mail, go to View → Message → Raw Source. In Outlook, open the email and press Ctrl+U.
Can tracking pixels be hidden in CSS too?: Yes. CSS background images, @import rules, and web fonts can all be used as tracking vectors. This tool scans visible HTML attributes; CSS-based tracking requires a different analysis.
What should I do if tracking pixels are found?: Enable your email client's image blocking or remote content blocking. Use an email provider with built-in tracking protection. Consider using the Strip HTML Tracking tool to remove the elements before forwarding the email.
Does this tool catch all trackers?: No tool can catch all trackers with certainty. Novel domains, obfuscated scripts, and first-party proxied tracking will not be flagged. Use this tool as a quick audit, not a definitive privacy audit.

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