Open source email

Open source email

What is open source email?

The term ‘open source email’ refers to email systems which use open source software. An email viewer is called an email client, so open source email systems use open source clients to display and compose emails.

Is Gmail open source?

No, far from it. Gmail is a proprietary email system, built and owned by Google / Alphabet Inc. Gmail uses sophisticated artificial intelligence to scan emails and collect data on their users. Read more about the privacy issues of Gmail.

What is the best open source email?


Nextcloud is an open source email client which also comes with a full suite of other office and collaborative tools, such as notes, calendar, contacts, tasks and file storage. It’s a complete alternative to Google suite, Dropbox and other cloud systems which can also sync between different devices and is easy to set up on laptop and mobile either via the app, or your existing email client. Nextcloud doesn’t provide a server, so if you want to use Nextcloud for your email you’ll still need to sign up with a provider like Open Web Systems to host your email or, if you know what you’re doing, you can run your own.


Horde is a full groupware system, and one of the options which ships by default with the ever-popular cPanel web admin system. The Horde suite is all browser based, and comes with email, calendars, contacts, tasks, and notes plus a PHP framework for building customised working environments. Like Nextcloud, Horde doesn’t provide a server, so you’ll still need a mail host, or to run your own. 


Roundcube is a modern webmail client that can be installed on a standard LAMP (Linux, Apache, MySQL, PHP) stack. Again, it doesn’t come with a mail server so you will need to sign up with a Rouncube email provider or install your own system on your own server. The user interface has some nice drag-and-drop features to let you customise the layout and Roundcube provides all the standard features you would expect from a decent email client such as canned responses, spell checking, and address book integration.


Zimbra provides hosted email and a webmail client, so is a direct alternative to a hosted Nextcloud instance, like Open Web Systems. It features most of the things you would expect including folders, contacts and  a number of pluggable extensions. A desktop client is also available.


Rainloop integrates with several online accounts like Facebook, Twitter, Google, and Dropbox for a more connected experience, but doing so will not protect your data from covert surveillance, so think twice before you link up your accounts. It’s easy to install, and you can try Rainloop in an online demo to see what it’s like.

Other options include Mailspring, Cypht, Mailpile, WebMail Lite and SquirrelMail most of which require a mail server to run.

Switching to open source email

If you’re looking to switch to open source email, for privacy or security reasons think carefully about which email host you will use, who owns the company and what their terms and conditions involve. If your mail host does not promise to be surveillance free your open source email client will not make much difference to your privacy. Switching can be very simple, if you sign up to Open Web Systems you’ll get an email with your new email credentials which you can use to log in to Nextcloud online, via the app, or you can continue to use your existing email client on your laptop or mobile by simply entering your new account details.

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