Open Source Proton Mail Alternatives

The best open source alternative to Proton Mail is Tutanota. If that doesn't suit you, our users have ranked more than 50 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 Disroot, Mailbox.org, Posteo and Skiff Mail.

Proton Mail alternatives are mainly WebMail Providers but may also be Email Clients or Calendar Apps. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of Proton Mail.

Proton Mail alternatives page was last updated

Proton Mail

746

Freemium • Open Source
WebMail Provider

Linux
Online
Android
iPhone
iPad
Tor

Secure email with absolutely no compromises, brought to you by MIT and CERN scientists.

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Tutanota
Is this is a good alternative?
Yes
No
Freemium • Open Source
Calendar App
WebMail Provider
Email Client
Mac
Windows
Linux
Online
Android
iPhone
iPad
Self-Hosted
Flathub
F-Droid
89 Tutanota alternatives
Tutanota is the world's most secure email service, easy to use and private by design. You get fully encrypted calendars and contacts with all our personal and business email accounts. It has open source iOS and an Android apps.
- - Tutanota is the most popular Web-based, Windows, Android & Mac alternative to Proton Mail.
- - Tutanota is the most popular Open Source & free alternative to Proton Mail.
Suggest and vote on features
Tutanota Features
1. Privacy focusedTutanota is considered a privacy friendly alternative.
2. End-to-End EncryptionTutanota has E2E Encryption, for entire or parts of the app.
3. Dark ModeTutanota supports dark mode for comfortable usage in low light conditions.
4. Multiple Account supportTutanota support multiple accounts without the need to logout and login
5. LightweightTutanota consumes less device resources compared to similar apps.
6. Email OrganizerTutanota allows you to take control of your inbox by filtering and control tools.
7. No TrackingTutanota will not track you or use your personal data.
8. Ad-freeTutanota doesn't contain any form of external advertising.
9. Calendar ViewTutanota has a built-in calendar view to have a clear overview of your content over time.
Encrypted Email
Custom Domain
Encrypted calendar
Contacts
Integrated File Sharing
Clean design
Full-Text Search
Spam Filter
Recurring Tasks
Auto Responder
Comments about Tutanota as a Alternative to Proton Mail
Almost everyone thinks Tutanota is a great Proton Mail alternative.
all • positive • negative relevance • date
Advik
Tutanota is end-to-end encrypted, as well offers 1 GB mail storage on free plan. The pro plans are cheap compared to protonmail, so it's better for low budget users
Top positive comment•
3

Conner Vieira
Tutanota has historically been a lot more transparent, and arguably has been more honest about issues and plans
Top positive comment•
-1

Ada Byron
I use both, ProtonMail is more secure but also more expensive and not as user-friendly. You cannot beat the price of Tutanota for service they provide.
Positive comment•
0

prechallenging_despitous
Cheap easy to use good clint
Positive comment•
-1

Guest
Tutanota does not allow immediate access. Must wait 48 hours to use.
Negative comment•
-14

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5 of 10 comments
Disroot
Is this is a good alternative?
Yes
No
Free • Open Source
WebMail Provider
Online
F-Droid
27 Disroot alternatives
Disroot is a platform providing online services based on principles of freedom, privacy, federation and decentralization.
Suggest and vote on features
Disroot Features
1. Privacy focusedDisroot is considered a privacy friendly alternative.
2. DecentralizedDisroot is based on a decentralized infrastructure with no single entity controlling it.
3. Ad-freeDisroot doesn't contain any form of external advertising.
4. End-to-End EncryptionDisroot has E2E Encryption, for entire or parts of the app.
5. Support for AliasesDisroot supports aliases, so you can receive email without exposing your main email address
6. No TrackingDisroot will not track you or use your personal data.
Encrypted Email
Can be used outside browser
IMAP Support
SMTP Support
Support for SFTP
Diaspora integration
Nextcloud integration
Cloud IDE
Comments about Disroot as a Alternative to Proton Mail
Almost everyone thinks Disroot is a great Proton Mail alternative.
Leonardo Eugenio
imap smtp support, open source, all free
Positive comment•
1

Guest
Simple, efficient, you can use it with Tunderbird or other mail client.
Positive comment•
0

Kris22332
Proton is not confidential at all, because it is under the influence of the EU. The best thing you can find for anonymous messaging and file sharing is the Utopia ecosystem (U.IS)
Positive comment•
-2
Mailbox.org
Is this is a good alternative?
Yes
No
Paid • Open Source
WebMail Provider
Email Client
Calendar App
Online
71 Mailbox.org alternatives
Mailbox.org offers a secure e-mail account for home and business use. The domain name, me@mailbox.org, is easy to remember and can be understood anywhere in the world. They have been operating e-mail accounts for more than 20 years and are a highly reliable service provider.
- - Mailbox.org is the most popular commercial alternative to Proton Mail.
Suggest and vote on features
Mailbox.org Features
1. Privacy focusedMailbox.org is considered a privacy friendly alternative.
2. PGP EncryptionMailbox.org supports PGP, an encryption system used for sending encrypted emails and files.
3. No TrackingMailbox.org will not track you or use your personal data.
4. Calendar IntegrationMailbox.org lets you sync your tasks and events with your calendar application.
5. Real time collaborationMultiple users can work together in Mailbox.org simultaneously.
6. Support for AliasesMailbox.org supports aliases, so you can receive email without exposing your main email address
7. Cloud SyncSync your data (notes, documents, bookmarks, etc.) across your different devices and to the cloud.
8. Self Destructing MessagesMailbox.org supports the use of private messages that will be auto deleted according to a specified time or action.
9. Spam FilterMailbox.org can detect unsolicited, unwanted and virus-infected emails, calls, files, etc.
Custom Domain
Encrypted Email
Built-in Calendar
IMAP Support
File Storage
Contacts
CalDAV Support
CardDAV Support
Support for SFTP
Two-factor Authentication
Comments about Mailbox.org as a Alternative to Proton Mail
Almost everyone thinks Mailbox.org is a great Proton Mail alternative.
John Fastman
Mailbox.org is a partial replacement for Protonmail. It offers a fully functional email solution (email, calendar, contacts), but with the added benefits of PGP encryption support (you can handle the keys or let them do it). It also allows you to send links to people who don't use PGP if you want to send private messages. For the encryption, it's a bit like Protonmail. For everything else, it's like a privacy-respecing Gmail alternative.
Positive comment•
2
Posteo
Is this is a good alternative?
Yes
No
Paid • Open Source
WebMail Provider
Email Client
Calendar App
Online
61 Posteo alternatives
Posteo is an independent email service provider. Based in Berlin since 2009. With focus on security, privacy, and sustainability. They offer ad free paid email accounts for individuals and businesses.
Suggest and vote on features
Posteo Features
1. Privacy focusedPosteo is considered a privacy friendly alternative.
2. Calendar IntegrationPosteo lets you sync your tasks and events with your calendar application.
3. PGP EncryptionPosteo supports PGP, an encryption system used for sending encrypted emails and files.
4. End-to-End EncryptionPosteo has E2E Encryption, for entire or parts of the app.
5. Dark ModePosteo supports dark mode for comfortable usage in low light conditions.
6. Ad-freePosteo doesn't contain any form of external advertising.
7. Email OrganizerPosteo allows you to take control of your inbox by filtering and control tools.
8. Spam FilterPosteo can detect unsolicited, unwanted and virus-infected emails, calls, files, etc.
9. Two-factor AuthenticationPosteo supports two-factor authentication (2FA).
Encrypted mail and contacts
Encrypted Email
Security focused
Transparency
Built-in Calendar
IMAP Support
Calendar View
Mail Filtering
Support for Aliases
No Tracking
Comments about Posteo as a Alternative to Proton Mail
Almost everyone thinks Posteo is a great Proton Mail alternative.
John Fastman
Posteo could be a good Protonmail alternative. It offers email encryption in a similar way: Posteo's people, government surveillance and successful hackers won't get into your email content. It also offers a calendar feature, which protonmail users have been crying out for for years.
Positive comment•
2
Skiff Mail
Is this is a good alternative?
Yes
No
Freemium • Open Source
WebMail Provider
Email Client
Calendar App
Online
Android
iPhone
49 Skiff Mail alternatives
Skiff Mail is private, end-to-end encrypted email. Sign up for 10 GB free storage, instant search, and total privacy.
Suggest and vote on features
Skiff Mail Features
1. Ad-freeSkiff Mail doesn't contain any form of external advertising.
2. No TrackingSkiff Mail will not track you or use your personal data.
3. Dark ModeSkiff Mail supports dark mode for comfortable usage in low light conditions.
4. Support for AliasesSkiff Mail supports aliases, so you can receive email without exposing your main email address
5. Two-factor AuthenticationSkiff Mail supports two-factor authentication (2FA).
6. Privacy focusedSkiff Mail is considered a privacy friendly alternative.
7. Spam FilterSkiff Mail can detect unsolicited, unwanted and virus-infected emails, calls, files, etc.
8. End-to-End EncryptionSkiff Mail has E2E Encryption, for entire or parts of the app.
9. Mail FilteringSkiff Mail classifies email messages according to specified criteria, allowing you to automatically recognize fraudulent or spam messages.
Encrypted Email
Custom Domain
Cross-device syncing
Email Organizer
Real time collaboration
Calendar Integration
Calendar View
Cloud Sync
Shared Folders
Reminders
Criptext
Is this is a good alternative?
Yes
No
Free Personal • Open Source
Email Client
Mac
Windows
Linux
Android
iPhone
22 Criptext alternatives
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.
Suggest and vote on features
Criptext Features
1. Privacy focusedCriptext is considered a privacy friendly alternative.
2. Support for AliasesCriptext supports aliases, so you can receive email without exposing your main email address
Discontinued
Creator recently sent and email about going solo, but since then support has been unresponsive, as have nearly all new issues on github for a year now if not more...

Comments about Criptext as a Alternative to Proton Mail
Almost everyone thinks Criptext is a great Proton Mail alternative.
Guest
Even thought Proton Mail is a good privacy focused email, it still holds both your emails and your keys on their servers. Regarding ownership, Criptext gives the user ownership over their keys, which reside only on the user's devices. It also uses Signal Protocol for encryption which I personally like better than just using pgp.
Positive comment•
3
Kolab Now
Is this is a good alternative?
Yes
No
Paid • Open Source
Calendar App
Mail Server
Cloud Storage Service
Online
Software as a Service (SaaS)
DAVdroid
76 Kolab Now alternatives
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.
- - Kolab Now is the most popular SaaS alternative to Proton Mail.
Suggest and vote on features
Kolab Now Features
1. Support for AliasesKolab Now supports aliases, so you can receive email without exposing your main email address
2. Real time collaborationMultiple users can work together in Kolab Now simultaneously.
3. Privacy focusedKolab Now is considered a privacy friendly alternative.
4. End-to-End EncryptionKolab Now has E2E Encryption, for entire or parts of the app.
CalDAV Support
WebDAV Sync
CardDAV Support