Mailspring
Fast, beautiful desktop email client with a unified inbox, snooze, send-later and read receipts — an open-source alternative to premium clients like Superhuman.
SuperhumanAbout Mailspring
Mailspring is a fast desktop email client that unifies every account you connect into one inbox, with the snooze, send-later and read-receipt features that made premium clients like Superhuman popular — without the subscription price tag for its core functionality.
It works with any IMAP account, so it isn't tied to a single provider, and its client-side code is open source even though the optional sync service and some Pro features require a paid plan.
Key features
- Unified inbox — Every connected email account appears in one combined inbox instead of separate windows.
- Snooze & send-later — Delay a message's arrival or send it at a scheduled time, the same way premium clients do.
- Read receipts & link tracking — See when a recipient opens your email or clicks a link (Pro feature).
- Works with any IMAP account — Not locked to a single provider — connect any standard IMAP or Exchange account.
The honest read
- Free desktop client with core features, no subscription required
- Unified inbox across every connected provider
- Pro features (read receipts, snooze) are affordably priced
- Works with any IMAP account
- Open-source client codebase
- Development pace has slowed compared to its early years
- Full feature set requires a Pro subscription
- Electron app is heavier on system resources than native mail apps
- No official mobile app
FAQ
Yes — the core client is free, with an optional Pro subscription for features like read receipts, snooze and link tracking.
The client application is open source, though the sync service backing some Pro features is not.
Yes — it works with any standard IMAP or Exchange account, including Gmail and Outlook.
Mailspring's core client is free and open source, while Superhuman is a closed-source, subscription-only product with a higher price point.
TypeScript
Electron
C++Similar open-source projects
Secure team messaging and collaboration for technical teams.
Customizable team chat with voice, video and omnichannel.
Threaded team chat that keeps async conversations organized.