zMail

zMail is a cross-platform, open-source email client and mail-server suite designed to provide fast, secure email access and routing. The project prioritizes privacy, extensibility, and a clean, responsive user experience across major desktop environments.

The client supports standard mail protocols including IMAP, SMTP, and POP3, and offers built-in end-to-end encryption options via PGP/GPG and S/MIME. It provides offline access, fast full-text search, labels and filters, and a keyboard-driven interface.

Development and design: zMail employs a modular, plugin-friendly architecture that enables extensions for calendars, tasks, and custom themes. A lightweight server component handles message routing, authentication, synchronization, and basic spam filtering, allowing a separation between client features and mail processing.

Contribution and licensing: The project is maintained by an active open-source community and released under an open-source license. The code and documentation are publicly available, with an issue tracker and contribution guidelines to invite user and developer participation.