mailopened — Supercharge your email tracking

If your open count stays at 0, it’s usually one of the following:

• Recipient hasn’t opened the email yet. The counter only increases when the pixel is requested.
• Important: You must click “Mark as Sent” in MailOpen after sending. If a message remains as “Draft/Not Sent,” opens aren’t counted.
• Remote images are blocked. Some clients (e.g., Outlook desktop) block remote images by default; the pixel won’t load until images are allowed.
• Apple Mail Privacy Protection (MPP). Apple may prefetch images via a proxy. You might see 1 open even if the recipient didn’t read it, or see delayed/aggregated behavior.
• Gmail image caching. Gmail fetches and caches images via a proxy; subsequent opens may not hit your pixel again, which can reduce total counts.
• Pixel not embedded or altered. Ensure the exact `` code from MailOpen is present in the final HTML body (not in plain text only).
• Plain-text emails. Pixels only work in HTML emails, not plain-text versions.
• Security scanners. Some gateways prefetch links/images, causing an early single open, then nothing further.

Note: Events are recorded when the tracking image is requested. They’re stored in UTC and (typically) displayed in your local time.

Copy the exact pixel HTML from MailOpen and place it at the very end of your email’s HTML body (just before the closing </body>). Do not resize or wrap it in conditional code.

<img src="https://mailopen.com/o/YOUR_PIXEL_ID.png" width="1" height="1" alt="MailOpen tracking pixel" style="display:block;border:0;outline:none;" />

If your editor strips HTML, switch to an HTML/source view or a platform that supports raw HTML in templates.

Yes. If the forwarded copy loads the image, MailOpen records an open. For campaigns where you need per-recipient accuracy, generate unique pixels per recipient (when available) so forwards don’t merge into the same count.

If you preview or open your own sent email and images are enabled, the pixel loads and counts as an open. For testing, send to a secondary address or view in a client that blocks remote images to avoid self-opens.

Unique Opens counts the first open per recipient per email. Total Opens includes all subsequent opens (e.g., each time the recipient re-reads the email or views it on another device).

• Gmail proxy caching: Gmail may only fetch your pixel once and then serve its cached copy thereafter, reducing Total Opens for repeat views.
• Apple MPP: Apple may prefetch images soon after delivery via a proxy, leading to a recorded open even if the user never read the message.

This is normal behavior across the industry and affects all pixel trackers.

Yes, but Outlook desktop often blocks external images by default. Recipients must allow images (manually or via policy) for the pixel to load and register an open.

No. Tracking pixels are HTML images. Plain-text emails don’t load images, so no open events are recorded.

1. Send a real HTML email with the MailOpen pixel embedded.
2. Use a mailbox that allows remote images (e.g., Gmail web, Outlook.com, or Apple Mail with images enabled).
3. Open the email and wait a few seconds; refresh MailOpen to see the open recorded.
4. If counts don’t change, view the email’s source to confirm the pixel URL is intact, and ensure you clicked “Mark as Sent.”

You can archive the message and create a fresh one (new pixel) to start from zero. For data integrity, historical events are typically not editable once logged.

MailOpen focuses on open tracking. Click tracking requires link-wrapping through a redirect service. You can pair MailOpen with your own redirect links if you need click analytics.

Most opens are logged instantly, but proxies, caching, and network conditions can delay requests. Also, Apple/Gmail proxies may batch or prefetch, affecting timing.

MailOpen records the open event timestamp and limited technical details necessary for analytics. No email message content is stored by the pixel. Refer to your organization’s policy and applicable laws before using tracking pixels.

Compliance depends on how you use it and where your recipients live. Obtain consent where required, provide notice in your emails or privacy policy, and follow local regulations (e.g., GDPR/PECR, CASL, CAN-SPAM). Consult legal counsel for your specific use case.

• Always click “Mark as Sent” in MailOpen immediately after sending.
• Send HTML emails with the pixel at the end of the body.
• Avoid very heavy images or tracking in signatures that recipients might strip.
• Ask internal recipients to allow external images (company policy can help).
• Expect proxy effects (Apple/Gmail); focus on trends over exact totals.