Seen is a privacy-focused email tracking extension designed for Gmail users who want to know when their emails are opened. It offers features like invisible tracking, smart filtering to avoid false positives, and real-time notifications across devices. The tool integrates seamlessly into Gmail, allowing users to track their emails without altering their usual workflow. With a focus on privacy, Seen does not add any identifying signatures to emails, ensuring that tracking remains discreet and professional.

This add-on is available for free with a daily usage limit, and users can upgrade to a Pro version for unlimited tracking and additional features such as detailed open history and advanced link analytics. Seen complies with GDPR regulations and maintains a strong commitment to user privacy by not selling data to third parties. Its design also accommodates dark mode for a consistent user experience.