I was researching WebMail providers, and noticed that most WebMail providers recommended in privacy communities are labelled as proprietary by AlternativeTo.
I made a list of WebMail providers, private or not, to see which ones were actually open source:
Proprietary
AOL Mail: Free
Cock.li: Free
CounterMail: Paid
Fastmail: Paid
GMX Mail: Free
Gmail: Free
HEY Email: Paid
Hushmail: Paid
iCloud Mail: Free
Mail.com: Free
Mailbox.org: Paid
Mailfence: Freemium
Outlook.com: Freemium
Posteo: Paid
Rediffmail: Paid
Riseup: Free
Runbox: Paid
Soverin: Paid
StartMail: Paid
Yahoo! Mail: Freemium
Yandex Mail: Freemium
Zoho Mail: Freemium
Open source
Criptext: Free
Disroot: Free
Forward Email: Freemium
Infomaniak kMail: Freemium
Kolab Now: Paid
Lavabit: Paid
Mailpile: Free
Proton Mail: Freemium
Roundcube: Free
Skiff/Notion: Freemium
Tuta: Freemium
Unless I’m missing something, it seems like people overlook this when deciding on WebMail providers. Is it a distinction between a proprietary backend server and a proprietary app, or is there a different way to decide if a WebMail provider is proprietary vs. open source? Lavabit was labelled proprietary by AlternativeTo, but open source by Wikipedia.
Note
If I have labelled an open source WebMail provider as proprietary by mistake, please provide evidence by linking to the source code, and I will happily change it.
Most “privacy” webmail providers, such as ProtonMail, Tutanota, and mainstream services like Gmail, Yahoo Mail, Outlook, and AOL Mail, are labeled as proprietary because they use closed-source software, meaning the code isn’t publicly available for review. These services operate on controlled servers, with features and infrastructures managed entirely by the company. The proprietary nature allows them to implement unique features and monetization strategies, but it also requires users to trust the company’s privacy and security practices without independent verification. This contrasts with open-source alternatives where users can inspect and verify the code themselves.
