Thunderbird is a open source mail client developed and maintained by Mozilla foundation. Developed by Mozilla Corporation
License: Open Source
Thunderbird is a free, open-source email client known for its strong customization and cross-platform support, making it suitable for users who value flexibility and privacy. Apple Mail, on the other hand, is designed for users within the Apple ecosystem, offering seamless integration and a user-friendly interface, but lacks the extensive customization options available in Thunderbird.