Open rate tracking in emails is done using a small, hidden image included in the email. When the email is opened, this image loads, indicating that the email has been read. This method is currently the only way to track open rates and is a standard practice across the industry. However, there are a few reasons why this might not always be accurate:
Email Service Providers and Proxies: Some email services, like Gmail, use a special method to open images. They use a proxy server that pre-loads images. This means the tracking image might be loaded even if the email isn't actually opened by the recipient.
Image Blocking: Some email services or users choose not to automatically load images in emails. In these cases, even if the recipient reads the email, the tracking image won't load, and it won't count as an open.
Due to these factors, open rate data can sometimes be unreliable, showing either more opens than there really were or fewer. Despite its limitations, this method remains the standard in the industry for tracking email open rates.