Email tracking pixel checker: find open pixels and tracked links in an email
In short: Reads an email's HTML or raw source: images that are 1×1, hidden or on a tracking-style address (with Mailchimp, SendGrid, Amazon SES and Postmark patterns named), link hosts that redirect clicks, recipient-side rewrites like Safe Links, and whether tracking runs on your own domain. Limit: It matches patterns and never loads anything, so a pixel on an ordinary-looking image address or set up by CSS background can be missed.
An email tracking pixel is a tiny, usually 1×1 image whose address is unique to the recipient: when it loads, the sender logs an open. Paste the email's HTML or the .eml source here to list every pixel, why it was flagged, and which links pass through a click-tracking redirect, including whether that tracking domain is your own.
Price: this tool is free. Checking a whole email list is from $9/mo, and the first 100 checks are free with Google, no card. See pricing
Sample result
A 1×1 image on u123.ct.sendgrid.net/wf/open: SendGrid open tracking is on.
- Open tracking
- 1 pixel
- Click tracking
- SendGrid
- Own domain
- 1 of 2 hosts
What this means for you
Links go through SendGrid's click tracking, not your own domain.
- Paste HTML or the .eml source
- 1×1, hidden and tracker-style images
- Click redirects by host
- Recipient Safe Links told apart
- Open tracking
- Click tracking
- .eml
By SimpleVerifier Team · Last updated · Runs in your browser; nothing you paste is sent to us
Tracking is sorted. Bounces still hurt the domain more.
- Export the list the campaign will go to.
- Upload or paste it at /verify. The first 100 email checks are free with a Google sign-in, no card.
- For every list after that, Pro includes unlimited email verification. Fair use: the first 100,000 checks a month at full speed, then slower, never cut off.
How do I check if an email has a tracking pixel?
- In Gmail use More > Show original, in Outlook view the message source or save it as .eml, and copy everything. Your own campaign's HTML works too.
- Paste it and press Check. Optionally enter your sending domain if you pasted HTML without headers.
- Read the pixels (with the reason each was flagged) and the link hosts: sender click tracking, recipient security rewrite, looks tracked, or plain.
- If you send cold email, decide whether to turn open tracking off and put click tracking on your own domain.
Example
- You enter
- A raw message from
[email protected]with a 1×1 image onu123.ct.sendgrid.net/wf/open, and links throughu123.ct.sendgrid.net/ls/click,track.northwind.example/c/…andwww.example.com/help. - You get
- 1 open-tracking pixel (1×1 or smaller; SendGrid tracking address). Link hosts:
track.northwind.examplelooks like a tracking redirect on your own domain,u123.ct.sendgrid.netis SendGrid click tracking,www.example.comis a plain link. - Limits
- Runs in your browser; nothing in the message is fetched.
How does an email tracking pixel work?
The email includes an image, usually transparent and one pixel square, whose address contains an ID for the recipient. When the mail app loads images, it requests that address and the sender records an open. SendGrid's own docs describe it as a transparent one-pixel image added to the end of the email.
Opens are less reliable than they look: Apple Mail Privacy Protection loads images in the background whether or not the person reads the email, and Gmail fetches images through its own proxy. Many clients don't load images until asked.
Does open tracking hurt cold email deliverability?
It can. A pixel on a tracking host shared by thousands of senders ties your message to that host's reputation, which you don't control. Many cold emailers turn open tracking off and measure replies instead; the open tracking guide covers the trade-off.
Click tracking rewrites every link to pass through a redirect. On a shared domain that's the same risk; on your own subdomain (a custom tracking domain, a CNAME such as track.example.com) the links match your brand. Amazon SES and the cold email platforms all support one; the custom tracking domain generator builds the record.
Why are some links rewritten even when I don't track clicks?
The recipient's security does it. Microsoft Defender Safe Links, Proofpoint URL Defense and Mimecast rewrite links in received mail so they can check them on click. If you pasted a message from your own inbox, those hosts belong to your company's filter, not the sender; the checker labels them separately.
Open tracking, click tracking or neither?
| What it records | Deliverability cost | How reliable | |
|---|---|---|---|
| Open pixel | Image loaded | A hidden image, often on a shared host | Low: privacy proxies load images unread |
| Click redirect, shared host | Link clicked | Links on another sender's domain | Good, but scanners click too |
| Click redirect, own subdomain | Link clicked | Links stay on your domain | Good, but scanners click too |
| No tracking | Replies only | None | Replies are what count |
Who uses this tool, and for what?
- Cold emailers
- Check a test send to confirm open tracking is really off and links use your custom tracking domain, not the platform's shared one.
- Marketers
- See which ESP's tracking a template carries after moving platforms, before the old pixel ships by mistake.
- Privacy-minded readers
- Find out whether a newsletter tracks your opens and clicks.
What can’t this tool tell you?
- It matches patterns and never loads anything, so a pixel on an ordinary-looking image address or set up by CSS background can be missed.
- A normal 1×1 spacer image in an old table layout is flagged too; check the address.
- Vendor names are given only for documented address patterns. Other tracking hosts are reported by shape.
Common questions
- How can I tell if an email has a tracking pixel?
- Look at the source for an image that's 1×1 or hidden and whose address carries an ID. Paste the source here and every such image is listed with the reason.
- Can tracking pixels be blocked?
- Yes, by not loading remote images: most mail apps have a setting for it. Apple Mail Privacy Protection and Gmail's image proxy hide your location and timing, though the open may still be counted.
- Should I turn off open tracking for cold email?
- Many cold emailers do, because opens are unreliable and the pixel adds risk. Measure replies instead, and keep click tracking on a custom tracking domain if you need it.
- Is the email sent anywhere?
- No. The source is read in your browser and no image or link in it is fetched.
Sources
Authentication and capacity are half of deliverability.
The other half is who you send to. Every hard bounce counts against the domain and inboxes you are sending from, and nothing in DNS can tell you which addresses on your list are dead.
- Bulk verification with real SMTP mailbox checks
- Hard bounces removed before a send, not discovered after
- Catch-all, disposable and role detection on every row
Plans from $9 a month, cancel anytime, no contract. Sign in with Google and your first 100 email checks are free, no card. The free tools stay free either way.