Mailspring

Mailspring is an open-source email client that optimizes performance with a C++ sync engine, significantly reducing resource usage compared to its predecessor, Nylas Mail. It features a modern, extensible UI built with Electron and React, offering tools such as Unified Inbox, Snooze, and Send Later, while maintaining user privacy by keeping operations client-side. Mailspring Pro enhances functionality with features like link tracking and mailbox analytics for power users.