Mailvelope is a free software for end-to-end encryption of email traffic inside of a web browser (Firefox or Chromium) that integrates itself into existing webmail applications. Developed by Thomas Oberndörfer
License: Open Source
Enigmail is designed for use with Thunderbird and focuses on PGP encryption for email, providing a more robust set of features for desktop users. In contrast, Mailvelope is a browser extension that allows users to encrypt webmail, making it more versatile for those who prefer web-based email services.