Compare software

Polymail vs Mailspring: catalog facts
Polymail	Mailspring
Paid Paid plans with a free trial.	Freemium The client is free and open source. Mailspring Pro is a monthly subscription that adds…
macOS, iOS	Windows, macOS, Linux
Read tracking and follow-up reminders inside email Several inboxes in one place	Unified inbox, snooze, send later, rules and templates in the free tier C++ sync engine keeps memory and battery use down for an Electron app
Requires a paid subscription after the trial Read tracking may not suit privacy-minded recipients	Read receipts and link tracking are paid, and are tracking features Electron, so still heavier than a native client
Downloadable app, Hosted service	Downloadable app
Closed source	Open source
License not stated	License: GPL-3.0
Account needed	No account needed
Not stated if it works offline	Works offline
Official website Full listing and sources Checked October 2, 2026	Official website Full listing and sources Checked September 21, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.