Appears to be desktop only. Signaling they are a Newton alt and sucessor of sorts. -- https://getmailspring.com/pro: "Powerful template support Rich contact profiles Follow-up reminders Read receipts Link tracking Send later Company overviews Snooze messages Actionable mailbox insights ...and much more!" -- For me, the depth of the read receipts and link tracking are most important. Most other stuff -- eh. It's desktop only any way. #mail #%homebrew_casks #electron_based #%github #best_of #desktop_apps_3_major_OSes #feature_rich #open_source #freemium #B2C #doesnt_look_like_electron #SaaS #B2P