5 open source alternatives to Gmail

Explore the world of open source alternatives to Gmail as you discover several options for free webmail clients to manage your inbox.
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A pile of paper mail

Judith E. Bell. Modified by Opensource.com. CC BY-SA 2.0.

Gmail has enjoyed phenomenal success, and regardless of which study you choose to look at for exact numbers, there's no doubt that Gmail is towards the top of the pack when it comes to market share. For certain circles, Gmail has become synonymous with email, or at least with webmail. Many appreciate its clean interface and the simple ability to access their inbox from anywhere.


But Gmail is far from the only name in the game when it comes to web-based email clients. In fact, there are a number of open source alternatives available for those who want more freedom, and occasionally, a completely different approach to managing their email without relying on a desktop client. You'll still need an email server to use with these clients. If you don't already have a favorite, look for an upcoming article with some options to consider.


Let's take a look at just a few of the free, open source webmail clients out there available for you to choose from.


Nextcloud is often thought of as file syncronization software (like Dropbox) but it's a lot more than that. By default, it's a sort of virtual drive in the cloud. Significantly, "the cloud" in this context can be your own server. In addition to being an interface to your online storage, it has a rich plugin system so you can run web apps for everything from chat to mail.


Nextcloud mail client

The mail plugin doesn't provide a mail server. It's just a webmail client, but it connects to a variety of mail systems. If you run Nextcloud on a server you have sudo or root access to, it's possible to setup Postfix or a similar mail server, and use the Nextcloud mail app as the front end. Best of all, Nextcloud devs have refrained from reinventing the wheel, and use libraries from the popular Horde mail client.


More than just a mail client, Horde is full-fledged enterprise-ready groupware. The Horde suite is browser based, and includes web apps for reading, sending and organizing email, managing and sharing calendars, contacts, tasks, and notes. In addition, the Horde project provides a PHP framework with libraries and apps for building out a customized working environment.


Horde groupware

Like the Nextcloud mail app, Horde doesn't provide a server, so you'll still need a mail host, or you can run your own. However, Horde offers a robust experience (you can demo it for yourself on their site) for managing your online life, and its UI is excellent on the desktop and mobile.


Roundcube is a modern webmail client that installs easily on a standard LAMP (Linux, Apache, MySQL, PHP) stack. It features a drag-and-drop interface that generally feels modern and fast, and comes with a slew of features: canned responses, spell checking, translation into over 70 languages, a templating system, tight address book integration, and many more. It also features a pluggable API for creating extensions.

Roundcube is available as open source under the GPLv3.


Roundcube screenshot courtesy of the project's website.


The next client on the list is Zimbra, which I have used extensively for work. Zimbra includes both a webmail client and an email server, so if you're looking for an all-in-one solution, it may be a good choice.

Zimbra is a well-maintained project that has been hosted at a number of different corporate entities through the years, and was acquired by Synacore in 2016. It features most of the things you've come to expect in a modern webmail client, from webmail to folders to contact lists to a number of pluggable extensions, and generally works very well. I have to admit that I'm most familiar with an older version of Zimbra, which felt at times slow and clunky, especially on mobile, but it appears that more recent versions have overcome these issues and provide a snappy, clean interface regardless of the device you are using. A desktop client is also available for those who prefer a more native experience. For more on Zimbra, see this article from Zimbra's Olivier Thierry, who shares a good deal more about Zimbra's role in the open source community.

Zimbra's web client is licensed under a Common Public Attribution License, and the server code is available under GPLv2. S


Zimbra screenshot courtesy Wikicommons, licensed CC-BY-SA.


Next up is Rainloop. Rainloop is a very modern entry into the webmail arena, and its interface is definitely closer to what you might expect if you're used to Gmail or another commercial email client. It comes with most features you've come to expect, including email address autocompletion, drag-and-drop and keyboard interfaces, filtering support, and many others, and it can easily be extended with additional plugins. It integrates with other online accounts like Facebook, Twitter, Google, and Dropbox for a more connected experience, and it also renders HTML emails very well compared to some other clients I've used, which can struggle with complex markup.

It's easy to install, and you can try Rainloop in an online demo to decide if it's a good fit for you.

Rainloop is primarily written in PHP, and the community edition is licensed under the AGPL. You can also check out the source code on GitHub.


Rainloop screenshot by author.

More options

  • Mailspring supports multiple accounts, read receipts, translations, undo send, and other popular email client features.
  • Cypht is a lightweight email client and news reader written in PHP and JavaScript and licensed under GPL v2. It's got a unique design aimed at combining several feeds (disparate email addresses and RSS feeds) into one.
  • Mailpile is an HTML 5 email client, written in Python, and available under the AGPL. Mailpile focuses on speed and privacy.
  • WebMail Lite is a modern but minimalist option, licensed under the AGPL and written mostly in PHP. It's feature-rich (it can even integrate OpenGPG) but simple to install.
  • SquirrelMail describes itself as "webmail for nuts". It's lightweight and simple to install, and has been around since 1999.

This is by no means a comprehensive list. What's your favorite open source webmail client?

Editor's note: This article was originally published in 2015, and has been updated to reflect changes in available software options.

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Jason Baker
Former Red Hatter. Now a consultant and aspiring entrepreneur. Map nerd, maker, and enthusiastic installer of open source desktop and self-hosted software.



Why would you want an open source email platform? Do you love being hacked?

Taco, do you like to troll?

In reply to by Taco (not verified)

You'd think that an open source program would be more vulnerable to attack, but it's actually the opposite. Because more people can see the code and its vulnerabilities, there's a better chance of those vulnerabilities being fixed. Once a vulnerability is fixed, it's just a matter of people updating their software. Linus' law: "Given enough eyeballs, all bugs are shallow"

In reply to by Taco (not verified)

I really like Horde's mobile UI, and the mail client was pretty easy to install separate from the rest of it. SquirrelMail and RoundCube are challenging to use on a mobile device. RoundCube has a supposed mobile plugin but I could not get it to work.


They are the upstream of Roundcube. The service is excellent and the nominal fee helps support upstream development of Roundcube and other very important open source projects.

I would recommend Horde, very complete system http://www.horde.org/

The title for this article is VERY misleading! It incorrectly implies (or at least one may infer) that you will NOT be using gmail.

Perhaps if it had the word 'client' in it... Better yet, because these 'clients' will work with any email service, leave gmail out of the title, i.e., "5 open source (alternative) email clients" would be much more apt and thus more informative and truthful ('alternative' in parens because not necessary). And I bet these clients are compatible with most other email services as well. Why are you choosing gmail?

Or did you intend that the title be 'click bait' because you needed traffic because you're losing audience..?

Other than that, good and informatve article... Thank you for the research/information

The author clearly states that these are web client alternatives to the popular Gmail (which is by far the most widely used web email service, hence why it was chosen over the many others that do exist). It then goes to say in order to use them, you will need to also host your own email server, and says a guide for those will be coming in the future. Zimbra though actually is also a server making it a complete package.

So, the title is accurate as this is a start to building a alternative to the popular Gmail service. Hope this helps. Thanks.

In reply to by tomo (not verified)

what about openmailbox?

RainLoop is awesome :) Very intuitive design

My favorite one is Tutanota: https://tutanota.com

It's the antipode of Gmail as it encrypts all your data. It is not possible to scan my data for advertisement or infringe my privacy in any way. Plus i can get the code from guthub and run the client locally. I'd be very happy to see an article here about Tutanota one day! If we want to get rid of Gmail, built-in encryption is the right way to go.

Curious about this. Can I run it inside of Thunderbird on a Linux desktop/laptop? I am all for keeping my data private, and have been looking for something to replace GMail.

In reply to by Jannis (not verified)

Only the Tutanota client is open source. Its server code is not open source. For that reason, we're still not including it in this list.

In reply to by Jannis (not verified)

Fail. Why? Because all of these are fat downloads and none are as easy as going to a webpage like gmail, creating an ID and viola, done! Your ordinary users are not going to download software just because they want email. Duh. Amazing how clueless these software and email client companies are.

They're not clients... All of these are server software, and by running one on a webserver you will have your own "webpage like gmail". Duh. Yes, it will take longer to set up than writing off your most sensitive information to Google, but you (or rather, an ordinary user with an ounce of patience) will have your mail in an environment that you control.

Amazing how clueless— nah, I'm not going to stoop to that.

In reply to by Johnjbfan (not verified)

I set up Squirrel Mail on a laptop server once for a demonstration. It isn't elegant but we were looking for ways to cut costs at our K-12 school district and this was a viable option.

These solutions are hosted solutions AKA you install them on a server and then you can use simply a web browser as you would for gmail and serve as many clients as you wich!

So they are indeed gmail server replacement!... ;-)

Yeah, OK for the client, but if your mails remain to be handled by the Google's servers, where is the gain ?

Mails need NOT be handled by Googles servers. You can choose any hosting provider you like or host it on an in-house server if you have enough bandwidth and are prepared to set up the security required.

In reply to by TP (not verified)

The Free Software Foundation maintains a list of Webmail serviices that treat users with respect -- readers of this article might find it interesting: https://www.fsf.org/resources/webmail-systems

Yes there are lots of open source webmail interface in market, which are lot good.

One of them which I use is and recommend is group-office open-source from https://www.group-office.com/ Also Horde Groupware webmail edition is great with support for mobile sync for calandar /contact/task/notes

Horde, round cube and squirrel mail do not support full mobile sync. Notes in particular is 100% not supported.

In reply to by deependhulla

I've run Zimbra, Squirrelmail and Round Cube in the best and they all do the front end job just fine - the hard part is the server end of things. Except for Zimbra, you have to either deal with the IMAP server supplied by a hosting company or set up your own (Zimbra includes an IMAP server). The big problem there is spam - filtering it and then trying to either filter more or tweak it to reduce false positives. It's a constant battle of keeping Spam Assassin up to date, RBLs, grey listing, SPF, DKIM, etc. I can't keep up with it just for an email box. Worse is hosting emails for others, now you have to research and explain why email x was put in the spam folder and email y was not. Finally, I caved and went to gmail and haven't looked back. Gmail, Office 365, Yahoo Mail, whatever your poison - all have spam filtering I could not replicate, high availability, ubiquitous clients - I can focus on my actual work instead of dorking around with mail server tweaks, updates, etc.

Have a look at ASSP, a PERL based anti spam Bayesian pre filter and run by a web interface. It's very solid and accurate, easily trained. I ran it for several years with only 2 restarts. It took about ten days to get to around 99.5+% accuracy provided you did the work to train it. Look for it at Sourceforge.

In reply to by rla (not verified)

It's true that in the US it's a bit less known but if you want to talk about complete and Enterprise ready Collaboration Platform then you should have a look at Zarafa: http://www.zarafa.com/

It's not just perfect as a MS Exchange replacement which uses a fraction of the resources and costs, it also includes video conferencing, instant messaging, file sharing, email encryption, etc...

Good post.

I used to install Squirrel. Worked allways very good. BUT: development stopped some years (more than 3) ago. Servers were attacked. There are no updates. Even not for security. Old php-versions requiered. So my firm recommendation is to NOT install this any more.

I switched to Roundcube and Rainloop. Both are stable and working well. You can easily use them in parallel. And I do this because each of them has advantages concerning the usability. Also, roundcube started crowdfunding to reprogram every part using modern frameworks. This will put it more to responsiveness.

These two programs are also perfectly integrated into my server control management.

I used to use Squirrelmail, and then moved on to Roundcube. The problem I've had with these has mainly been that it uses the old folder paradigm (thus also requiring an external system for filtering rules). Sieve scripts are fine for neckbeards but definitely not the sort of experience that most users are going to want. I've not really seen anything yet that uses labels & views with integrated rule policies.

Why are all the comments' dates so old? Is this a repost or smth?

Anyway, I run kmail for my email but I like Roundcube pretty much (I work for a web hosting company so setting up my own mail server is not an issue :) ).

At work we started using OpenXchange recently, which is nice, but I still prefer Roundcube for my ocassional use.

that was my thought too. must be a repost. there also were more than 3000 votes within a day of posting, which is somewhat unusual.

i don't mind a repost of an article that is still current, but anything that reports on software applications aught to be reviewed to remove what is no longer current and add new things developed since then.

greetings, eMBee.

In reply to by Ricardo J. Barberis

As for me, the title is confusing and leads to a misunderstanding.
Because all of so-called 'alternatives' are not actually alternatives to Gmail. You use Gmail client in your webbrowser and the 'client-ware' resides in the Google cloud, you do not install anything on your desktop or home or company Intranet. In order to use an 'alternative' you need installing the whole infrastructure. If you want to use it everywhere - you have to expose it in the Internet, which always brings security threats. Otherwise - you are bounded to your Intranet.

Hosting your own email server to take back control of your privacy and data isn't that difficult at all.
Many small businesses have or can get decent connectivity, at least in metropolitan areas, and can get a public IP so they could setup their own services knowing nothing or very little about Linux by using platforms like ClearOS, Univention or Collax to mention a few on top of which they can install with a few clicks a replacement for GMail. I personally use/recommend Kopano but if you need basic features others will do.

Private users can do a similar thing by renting a small VPS for $5/10(?) a month and install, or get their nerdy friends to install, their preferred GMail replacement.

True that it's more convenient to use "Cloud" services as it's convenient to let other people decide for you but then they can't complain if their data gets lost or is used against them.

In reply to by Paweł (not verified)

This article is misleading for sure and misses the point a lot. However, an Open Source Alternative to this implies that you will host it yourself somewhere so you provide the cloud.

If you setup a mail server and then one of these clients then you don't have to install anything locally and install you just use the web versions of these clients.

Mail Server + Rainloop on a public facing server = your personal email cloud.

This article skips the Mail Server part which is easily the most important thing and that is unfortunate. You can't connect Rainloop to a server that doesn't exist. This was not a very well thought out article.

In reply to by Paweł (not verified)

It seems like this article has been "re-dated".

I take the opportunity to let you all know that the Open Source alternative to GMail & even Office365 is Kopano, the evolution of Zarafa, which now sports also integrations with MatterMost (MS Team/Slack services) and LibreOffice Online.

Kopano is available in Debian, Ubuntu, OpenSuse and Fedora repositories, as source code and as packages ready to use for most Linux distributions. See https://kopano.com for more info.

thank you, that's the kind of news i am looking for when revisiting an old topic.
i hope to see more comments like that.

greetings, eMBee

In reply to by Paolo Vecchi

zimbra is ok to compare to a email suite like google. I miss zohomail from this list. Now, talking about roundcube, squirrel, made me travel back in time, really. These things are soooo 2004. I remember more than 10 years ago people telling me to use roundcube because it was made using AJAX... hahaha.. boy I feel old now. Although those tools are still available and have modern install methods like iredmail, how would you make your clamav and spamassassin good as Gmail's antivirus and antispam. Sum up with greylisting, content filtering, the amazing interface and filters... config tools far beyond webmin/cpanel dashboards. Sometimes you have to leverage your things to available free tools and focus on what it matters. And if your email is too important to be handled by google like as if you are a government or something, I would go for a paid solution like IBM email or try out with zimbra and zoho. cheers guys.

It would be great if the author went further than writing a superficial description of these mail clients. It is obvious he has not tried some of the applications, at least not recently. Doesn't he know, for example, that SquirrelMail is currently a dormant project?

This is not really an alternative to GMail because you only covered the client side of things so you still need an email server which this article doesn't address at all. Article = Incomplete, Pull Request Denied

I think it's hilarious that pretty much all of the complaints on this article are from people who clearly didn't read it. Is this a repost? Yes, it says at the bottom it was originally posted two years ago and updated. Do you still need an email server to use with your webmail client? Yes, the author literally says that in the second paragraph.

Not an overly helpful comment. Might explain the name Grumpy.

In reply to by Grumpy Tux (not verified)

I Am Still using GroupOffice ..and its too fast compare to gmail for me .

I agree with some of the later comments, that perhaps the article needs a little more depth. Especially, if you're a Gmail user, why would you want another email client? Are you trying to consolidate email? Or are you looking for a better user experience? If so, what are the advantages of getting away from webmail to, say, a native client?

And there was a comment about the article being incomplete since it does not include mail servers and this may be true too.

I think some foreground explaining why this article is important would have helped.

I recently switching my hosting from GoDaddy to another company and quickly realized that their webmail client was actually pretty good with the exception of using HTML messages with images where I had a lot of problems as I use this often.

I settled on Roundcube but it feels dated and has some limitations I had to get used to also, most notable with use of bcc: which I use extensively in conjunction with Highrise. I'm trying to see if any of these other clients may be a better fit.

There is also https://privmx.com which is an alternative mail system, end-to-end encrypted by design. Could be useful in some situations.

I used Roundcube. I like its drag and drop feature.

And another alternative to google mail monopoly?

Thanks in advance

Running a secure email server these days is a full-time job. I pay for a personal ProtonMail account (https://protonmail.ch). No ads or snooping through my e-mail content by a "big-brother" hosting service like Google or Yahoo. ProtonMail is modern, private, secure e-mail with excellent SPAM filtering at a reasonable cost.

I love roundcube

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