Free Alternative to SpyPig

What Is An Invisible Image?

Invisible images (tracking pixels) are tiny files embedded in email HTML.

They load automatically and can signal that an email was opened.

  • SpyPig offered free email tracking via a small embedded image.
  • The service appears inactive as of May 2023.
  • Alternatives include Bananatag, Mailtrack, and Hubspot Sales.

What happens when you open an email:

  • Your email client requests the image from the sender’s server.
  • The request includes timing and basic device/network info.
  • Marketers use it to measure opens, clicks, and engagement time.
Email Sent Tracking image embedded Recipient Opens Email client requests image from the server Server Logs Time, IP, device info Analytics dashboard updates with open and engagement data
flowchart LR A[Email Sent] --> B[Recipient Opens Email] B --> C[Email Client Requests Pixel] C --> D[Tracking Server Logs Request] D --> E[Analytics Dashboard Updates]

Privacy note:

  • Tracking pixels can be a privacy concern for recipients.
  • Disable automatic image loading to reduce tracking.
  • Some email clients block tracking images by default.
Email tracking example
IP logging data
Go To IpLogger

How it works (simple version):

  • Email opens trigger a request to the tracking server.
  • The server logs the request as an “open” event.
  • Any server-side language can handle the logging.
  • The pixel is just an HTML img tag pointing to that server.
Did You Know?
  • Grabify.icu offers a simple tracking tool.
  • You embed an invisible image in the email.
  • You get a notification when the email is opened.