An invisible pixel is added
The extension catches the moment you hit "Send" in Gmail and attaches a transparent 1×1 image to the end of the mail. The recipient notices nothing; the mail looks exactly as usual.
Gmail Mail Tracker · Chrome Extension (Manifest V3)
A personal tool that shows whether the email you sent has been opened, when it was first and last opened, and roughly how many times. The same read receipt technique as Mailtrack, Streak and HubSpot Sales — an invisible tracking pixel — but your data stays on your own server, with no subscription.
When you send a proposal, a CV or an important email, there's only one question: did they open it? Gmail won't tell you. This tool quietly places a marker on your outgoing mail; the moment the recipient opens it, a notification lands on your desktop and the panel shows "Opened · 2×". So you decide when to send the follow-up from data, not guesswork — in short, an email tracking tool.
A clear "opened / not opened" status for every message you send.
A timestamp for when the recipient first saw the mail and last returned to it.
An approximate counter of how many times it was reopened (e.g. 3×).
The technique is called a tracking pixel: an invisible 1×1 image is added to the mail. The image lives not in the recipient's inbox but on your server — so its loading = a "mail opened" signal.
The extension catches the moment you hit "Send" in Gmail and attaches a transparent 1×1 image to the end of the mail. The recipient notices nothing; the mail looks exactly as usual.
When the recipient opens the mail, their email client sends a request to the server to fetch that tiny image. The request is logged instantly with a timestamp — not who, just the "opened" fact.
The extension polls the server periodically; on a new open, a desktop notification and an icon badge appear. In the panel, each mail is listed as "Opened · Nx" with its first/last open time.
A desktop notification and a badge on the extension icon the moment the recipient opens the mail. No need to keep Gmail open; it runs in the background.
Click the extension icon: "Opened · Nx" for each mail, first and last open time at a glance. Not a complex CRM — just enough.
Open records are written not to a third-party service but to a tiny SQLite file on your own server. As a Mailtrack alternative, you're in full control.
The extension asks only for storage, alarms and notifications; read access is limited to a single domain. No unnecessary permissions, no data collection, no ads.
A two-part, deliberately small architecture. On the front end, a modern Chrome extension (Manifest V3); on the back end, a single-folder PHP 8 + SQLite service. The server side is not a framework but portable, near-zero-maintenance plain PDO. On the chrome extension development side, permissions are kept to a minimum; each component does one job.
A Chrome MV3 extension + a tiny PHP/SQLite backend. Install it on your own server, your data stays with you. The package contains no token — you generate your own token during setup.
Setup: unzip → rename backend/config.example.php to config.php and enter your token → chrome://extensions → Developer mode → Load unpacked.
By the nature of the read-receipt technique, the same limits apply to every tracker. Instead of overselling the tool, I'd rather be honest about them:
The first-open signal is strong. Since Gmail won't give you read receipts, this pixel method is in practice the most solid indicator.
Gmail routes images through a proxy and caches them; a second open often generates no new request. That's why the count is approximate.
The recipient's location or device is not shown; only Google's proxy IP is logged. This tool doesn't say who or where — only "opened".
Apple Mail's privacy protection or a corporate security scan can show "opened" before the recipient has read anything. The panel flags suspicious early opens.
This extension was a personal solution; once the need is clear, it takes a day to design and runs for years. Let's talk for 15 minutes about a similar browser extension, automation or integration.