Mailspring is a new version of Nylas Mail maintained by one of the original authors. It's
a new C++ sync engine based on Mailcore2. It uses roughly half the RAM and CPU of Nylas Mail
and idles with almost zero "CPU Wakes", which translates to great battery life. It also has
an entirely revamped composer and other great new features.
Mailspring comes packed with powerful features like Unified Inbox, Snooze, Send Later, Mail
Rules, Templates and more. Mailspring Pro, which you can unlock with a monthly subscription,
adds even more features for people who send a ton of email: link tracking, read receipts,
mailbox analytics, contact and company profiles. All of these features run in the client -
Mailspring does not send your email credentials to the cloud.