I always wondered if people actually open the emails I send. Not in a creepy way, more like when you send a cold email or follow up, you just want to know if it landed or got ignored.
So I built Magio. It is an open source email view tracker with a Gmail extension and a real time analytics dashboard. The flow is dead simple. You compose an email in Gmail, the extension auto embeds a tiny invisible tracking pixel, and when the recipient opens it, the pixel fires back to your server with the view details.
The extension adds a toggle right next to Gmail's Send button so you can turn tracking on or off per email. When you open a sent email, a Streak style sidebar pops up showing how many times it was viewed, from which IPs, and when. The dashboard gives you an overview with charts, per email drill downs, and a session table with browser and device detection.
On the backend, it is a Next.js app with Prisma and PostgreSQL. The tracking endpoint returns a 1x1 transparent GIF with no cache headers so every open gets logged. It also filters out your own IP so you do not inflate your own view counts.
I also built a Plasmo based Chrome extension that hooks into Gmail's compose and reading views. The whole thing ships with Docker Compose so you can self host it in minutes.