When comparing Roundcube vs ProtonMail, the Slant community recommends Roundcube for most people. In the question“What are the best free and open source email providers for Linux?” Roundcube is ranked 2nd while ProtonMail is ranked 4th. The most important reason people chose Roundcube is:
Licensed under GPL v3 with code available on [GitHub](https://github.com/roundcube/roundcubemail).
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Free and open source
Licensed under GPL v3 with code available on GitHub.
Pro Actively maintained
As of 2022 it is still maintained.
Pro Plug-in support
Roundcube allows third-party plugins and has a temporary plugin repository (until the official plugin repository comes out of beta) with over a hundred plugins available, covering authentication, improved security and settings among many others categories.
Pro Sophisticated address book
Each contact can have their e-mail address, phone number, location, photos and associated URLs added to them. You can then group contacts and address your mails to the group instead of having to enter each person separately. Additionally, you can import vCards and CSV files as contact information. And, it has LDAP connectors.
Pro Access control support
Roundcube has built-in support for access control lists (ACL).
Pro Multiple identities
You receive mail from multiple sources in one account.
Pro Drag & drop support
Roundcube supports attaching files simply by dragging and dropping them in.
Pro Multilingual
Roundcube is available in over 70 languages.
Pro Auto-refresh
Has auto-refresh functionality for email boxes.
Pro Good documentation
You have access to the documentation for APIs as well plugins development.
Pro Built-in caching
Roundcube caches messages to allow quicker access to your mailbox and to alleviate the strain put on the server. You can turn off caching (change 'enable_caching' property in your config/main.inc.php file) if you need messages to appear instantly.
Pro Reactive UI for mobile
With elastic skin, Roundcube has an excellent UI also on mobile devices since version 1.4.
Pro CardDAV addressbook integration
CardDAV integration available via rcmcarddav plugin.
Pro Spell checking
You can enable/disable spellcheck by changing "enable_spellcheck" in main.inc.php file.
Pro Built-in end-to-end encryption
Pro No personal information needed
To create an account you don't need to give any personal information, just choose username, domain, and password. Even the recovery email address is optional.
Pro Privacy respecting
User data is protected by strict privacy laws because all servers are located in Switzerland.
Pro Open Source
Pro Mobile apps
Apps for Android and iOS available.
Cons
Con Klu
Unfortunately, all interfaces of roundcube look very old. I hope there will be a progress soon, Google Mail and Outlook Webmail should be the role models here. But also Yahoo mail offers an intuitive design.
If this open source software should survive, it must be completely renewed and bring up to new standards.
Con Themes
Not easy to create your own themes.
Con Mobile use
Does not translate to mobile use very well
Con For search there is no reverse index
This means it is very slow.
Con Extremely clunky unintuitive interface
For example the mouse cursor may start getting stuck and lag.
Con Search option are limited
You can only search for one item at a time instead of multiple search terms, which makes it difficult to go through large amounts of emails.
Con You can't make multiple accounts
It is not possible to make more then one account.
Con Javascript-intensive Webmail
Free accounts are required to use Javascript webmail and encryption is done in the browser. Javascript cryptography is harmful for security and should not be used.
Con Encryption Keys are stored server-side
The keys are generated during account creation. Using your existing keys is prohibited and ProtonMail must store and control the private keys. Encryption cannot be secure unless the user controls the private keys.
Con Still lacks some useful features
At the moment, there is no calendar feature and contact management is quite poor. They will, however, start to work on it.
Con Ties to US Investors
ProtonMail takes money from US Investors
Con No IMAP and SMTP support for basic accounts
Basic accounts are restricted to the Protonmail web client. Support for IMAP and SMTP is available with a paid subscription only, and as such with basic accounts it is not possible to send and receive email with external applications.
Con Overly expensive for desktop support
Con Requires phone number for login
If you sign up over Tor or a VPN, it will require email or phone number verification. Email verification is disabled if you use an email that isn't from Google or Outlook.