Mailspring

Mailspring, an open-source email client, offers a range of powerful features, such as a unified inbox, snoozing, scheduling, email rules, templates, and more.

The Mailspring Pro version, which you can unlock with a monthly subscription, offers even more features for users who send large volumes of emails: click tracking, read receipts, inbox analytics, and contact and company profiles. All of these features run directly within the client—Mailspring does not send your email login credentials to the cloud.

• Multiple accounts (IMAP and Office 365)
• Support for touch controls and gestures
• Advanced keyboard shortcuts
• Lightning-fast search across all accounts
• Cancel sending
• Unified inbox
• Grammar and spelling check in the compose window
• Deep integration with Mac, Windows, and Linux
• Custom themes and dark mode
• Localization into 12 languages