The best open source alternative to Proton Mail is Tuta Mail. If that doesn't suit you, our users have ranked more than 100 alternatives to Proton Mail and many of them is open source so hopefully you can find a suitable replacement. Other interesting open source alternatives to Proton Mail are Posteo, Disroot, Infomaniak kMail and FlowCrypt.
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.
Disroot is a platform providing online services based on principles of freedom, privacy, federation and decentralization.
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.
FlowCrypt (formerly CryptUp) is the easiest PGP encryption for Gmail. It behaves just like standard email, except it's encrypted.
Kolab Now provides a suite of intuitive apps in a user friendly environment to make your day to day online comms easier, smarter and most importantly; secure.
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.
Forward Email is the best email service, encrypted email service, and fastest email service. It supports unlimited domains and aliases for no extra cost. It uses quantum safe ChaCha20-Poly1305 encryption and offers SMTP, IMAP, POP3, email webhooks, email regular expressions...
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...
Zero is an open-source AI email solution that gives users the power to self-host their own email app while also integrating external services like Gmail and other email providers. Our goal is to modernize and improve emails through AI agents to truly modernize emails.
Cloudflare Workers-based email solution providing multiple address generation, attachment storage via R2, responsive web interface, RBAC management, Resend bulk email, Telegram or third-party forwarding, verification code recognition, and ECharts analytics.
Systemli.org is a left network and technics-collective that was founded in 2003. Our aim is to provide safe and trustworthy communication services. The project addresses political activists and people who have a particular need to protect their data.
Germany
EU
Netherlands
Switzerland
United States
China
Functions on secure browsers like Klar and Tor.