The best open source Email Client alternative to Gmail is Proton Mail. If that doesn't suit you, our users have ranked more than 100 alternatives to Gmail and nine of them are open source Email Clients so hopefully you can find a suitable replacement. Other interesting open source Email Client alternatives to Gmail are Tuta Mail, Posteo, Infomaniak kMail and Swisscows.email.
Proton Mail provides secure email services with end-to-end encryption, ensuring data protection. Swiss-based and outside US jurisdiction, it offers a free version to champion privacy as a human right. Fully accessible on any device.
Offers comprehensive encryption for email, calendar, and contacts with zero personal info required. Built on open source, install via Play Store, F-Droid, or APK, with Tor and VPN support. Both free and paid plans; utilizes quantum-resistant encryption ensuring privacy-focused, anonymous usage.
Web- and IMAP-based email service. 4GB cost 1€/month. Information is hosted on encrypted hard drives. Electricity from renewable resources is used.
Privacy-focused Swiss email system provides 20 GB free storage, supports custom domains and unlimited storage, syncs contacts and calendars, is ad-free, and is part of a secure productivity suite used by over a million users across Europe on all devices.
Swisscows.email is another product of Swisscows AG. This product offers you secure email traffic. With Swisscows.email you can send your emails encrypted so that absolutely no one can read them. The service is comparable to a letter that is protected from prying eyes in an...
Fripost – the Free Email Association. Fripost organize the people who want an alternative to "free" e-mail services where you are constantly under surveillance and personal data is handed over to third parties.
Finally, an email service that's built around your privacy. Get your @criptext.com email address and see what it's like to have peace of mind and privacy in every email you send.
Unofficial, free and open-source Google Inbox Desktop App. Built using electron, Inboxer includes a menu bar which is globalmenu compatible and works, and keyboard shortcuts.
Enterprise-level, browser-based suite for IMAP email, calendar, contacts, tasks, notes, wiki, and file management, offering syncing, shared and unlimited resources, multilingual support, customizable dashboard, and integration with mobile and external clients.
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Protonmail is free, open-source, encrypted (more private). Lacks: calendar & good contacts feature, but these are in the pipeline. Protonmail cannot by design data-mine your software for it's own profit; Gmail makes it's money by violating your privacy that way.