The Top Open Source Email Servers in 2024

By James LePage
 on September 28, 2021
Last modified on January 7th, 2022

The Top Open Source Email Servers in 2024

By James LePage
 on September 28, 2021
Last modified on January 7th, 2022

Are you searching for a perfect open-source email server software but don't know where to begin? Perhaps you're a business owner, and you have little technical know-how of comparing open-source software? 

Take a deep breath. You've landed in the right blog post. We've made things a tad easier for you by compiling a list of open-source email servers. Why? Because we know that choosing a perfect open-source email server solution can be daunting. More so, if you're not sure where to begin searching.

On each solution, we go through its features and tell you how your business can benefit from using it. This way, you don't have to scour the internet reading each article on an email server that we've reviewed. 

We'll kickstart this topic by answering this crucial question:

Why does using an open-source email server matter?

Using an open-source email server offers many benefits to businesses. The essential advantage is, you will be using a free email server platform. But also, you will receive numerous emails, filter spam emails, and block many unwanted emails. For instance, email servers like Gmail and Yahoo have functionality that users can use to block spammers. You can also link them up with your calendar, video conferencing, and other tools when it comes to integrations.

email menu on monitor screen

In comparison, when you use a proprietary email server, you have to pay for almost everything. On top of this, you get a limit on the number of emails that you can send. For instance, with the GoDaddy plan, you can send only between 80 and 300 emails, depending on the plan that you choose. Paying for your email comes with another challenge too. For starters, sometimes your emails won't be 100% secure. And maybe certain functionalities that your emails won't have. 

Advantages of using open-source email servers

There are many advantages of using open-source email server software. Here are the main ones we think you should know: 

  • You can have an unlimited number of email accounts. When you use an open-source email server, you can create as many aliases as you want and send thousands of emails. 
  • You don't pay any subscription fees. If you want to add 100 users, you can do so without being charged per user. This way, you will save money and grow your business quickly.
  • You get 100% control over your inboxes. You can set limits, policies and decide on the number of users you want to add. 
  • You will enjoy security. More open-source email servers are more secure than proprietary software servers. They allow you to beef up security by integrating with other tools. 
  • You get excellent customer service- Some open-source email servers offer the best support than closed source servers. They also give feedback on every email. For instance, you know if customers delete, open, or ignore your emails. 

Which components should you consider? 

If you choose an open-source email server, take a moment to evaluate things. Use the below questions to review each email server thoroughly.

  • Does the email server have a Mail Transfer Agent (MTA)? The MTA is what enables a server to send Emails from different users. 
  • Does it come with a Mail Delivery Agent feature? This functionality sends emails to your inbox. 
  • Does it come with IMAP and POP3 Server? These two features come in handy when you hand the mail clients' software. 
  • Does it have a spam filter feature? It is what you will use to block incoming spam. 
  • Does it have Antivirus? This feature analyzes and protects you against viruses and Trojans. 

What is open-source email server software? 

Open-source email servers software is any solution that individuals and businesses use to handle incoming and outgoing emails. We say they are open-source because you don't have to pay for them, and they are available to anyone to use them. 

Example: Think of an email server as a virtual post office, or a place where people collect or send mail. Major differences between email servers and post offices: 

  • At traditional post offices, it takes days, sometimes even before you receive your mail.
  • In contrast, open-source email servers allow you to get mail immediately.   

Examples of open-source email servers that most people use include Outlook, Gmail, and ProtonMail. Some open-source email server solutions that you should consider:

1. iRedMail

 iRedMail is one of the open-source email servers that any small business owner should consider. Installing it is easy, but it can be a lot quicker if you hire a professional to configure it for you. Just make sure that you go through iRedMail policies before deploying it. 

We recommend it because it comes with a myriad of features. Plus, it is also free. iRedMail is secure, which means no hacker can infiltrate your emails. You will get bug fixes and updates from Linux without paying anything. It is a perfect email server any startup entrepreneur can use to grow a business.


When you use iRedMail, you will get the following features:  

  • All your emails will be secure - You and your team members will access iRedMail only through secure connections. iRedMail encrypts your mail with POP3/IMAP/SMTP over TLS and stores your passwords in SSHA512 or BCRYPT (BSD) format.
  • You can sync all your contacts and calendar with iRedMail. Whether you manage your tasks on your computer, tablet, mobile phone, iRedMail lets you do it. 
  •  You get more than one account—no need to pay for mailboxes. iRedMail allows you to create as many mailboxes as you want. 
  • Everything works on Ubuntu, Red Hat Enterprise Linux, CentOS, Debian, Ubuntu, FreeBSD, and OpenBSD. 
  • iRedMail's backend is impressive: You'll get MySQL, MariaDB, and PostgreSQL.  
  • You and your team will get antispam and Antivirus.
  • iRedMail is compatible with many domains and mailing lists.
  • You have an option to choose a pro edition and enjoy more admin panel features. 
  • iRedMail runs on Debian, Ubuntu, CentOS, Fedora, Red Hat Linux, FreeBSD, and OpenBSD.
  • It has a third-party integration feature.

2. Github

Ask any developer where they store codes, most of them will mentionGitHub open source. We recommend it for its transparency and ease of use. You can use GitHub to pull requests and merge features for your email applications. GitHub also offers an excellent platform for anyone to review features. Or to collaborate with developers and make suggestions on the project. You can organize files in a way that can be easy to access. 

Github's interface is intuitive that won't take long to figure out. Plus, tons of FAQs can guide you on how to use it. 

Example: James owns Email Now, a SaaS that offers an emailing solution to independent schools. PayNow's developer uses GitHub as a code hosting platform. The support team uses Email Now to raise bug issues, then developers get a notification and resolve them at once. Apart from that, Email Now's dev team uses Github to do code health reviews. 


Github comes with the following features:

  • Github allows you to automate development workflows. 
  • You can use GitHub to build, test, and deploy your codes faster than your competitors.
  • You also get software packages that enable you to do private and public hosting.
  • You will get a flexible API that allows you to link up with other solutions.
  • Github allows you to create and publish on any website. 
  • You can also use GitHub's Marketplace to build, improve and speed up workflows. 
  • You get Webhooks API to integrate with Zapier. 
  • Github allows you to use Linux, Windows, and macOS tools to boost your workflows. 
  • You get 100% control over projects by using labels and groups. 
  • Github allows you to increase security across multiple repositories. 
  • Review your codes anytime, and make improvements anytime. 

3. James Apache

Another open-source email server you should consider isApache James. Some people call it Java Apache Mail Enterprise Server, and others call it James. It doesn't matter what you name it, and the fact is it is an open-source (SMTP and POP3 mail transfer tool) free server written in Java. Various contributors of the Apache Software Foundation maintain it. Some of the first contributors of the James Apache include Serge Knystautas, who is responsible for adding a preview version 3.0-M2, which now requires Java 1.5 or later.

Anyone can write mail-handling code and update the database. James Apache also allows you to filter spam, archive your messages, and develop your way of classifying them. You will love most about Apache James because it will enable you to create pure Java libraries. 


Apache James comes with the following features: 

  • Apache James has an SMTP feature that allows it to send email faster. 
  • It has an IMAP4 Protocol that retrieves email messages pronto. You can also use this functionality to download and manage messages. 
  • The Apache James has a straightforward implementation, which means you will get your Email in a few days. 
  • Apache James is compatible with the METADATA extension (RFC-5464).
  • The Apache James has a POP3 protocol feature, which means you will send messages faster. 

4. hMailServer

hMailServer is another open-source email-server software anyone can use, from states to companies, nonprofits, and more. We recommend it because it works well with any email protocol like POP3, SMTP, etc. What's more, hMailServer is compatible with webmail solutions. It has a user-friendly dashboard and tons of features that will make sending and receiving emails pretty easy. Plus, it has a robust spam protection functionality and virus scanner feature. You can use hMailserver as a forwarding email server for internal notifications. 


hMailServer has the following features: 

  • hMailServer has unique Antispam features, which means you'll be able to manage your spam mail. 
  • It supports IMAP and SMTP.
  • hMailServer is compatible with RoundCube and SquirrelMail.
  • It has a feature that allows you to collaborate on projects. 
  • You can sync it with webmail. 
  • You can use hMailServer to create a database for your business.
  • It comes with file-sharing functionality.
  • It allows you to block notifications. 
  • You can have a group Live Chat.
  • You can use it to protect your password.
  • You get free presentation tools.
  • It has a one-click join feature.
  • hMailServer comes with a screen recording feature.
  • It allows you to switch presenters.

5. Mail-in-a-Box 

You should consider a Mail-in-a-Box email server, especially if you want to host your own email. Interestingly, this open-source email server works more like a typical Gmail account, and the only difference is that you get more control over your account than on your Gmail. Plus, you don't have to be a technocrat to set it up. 

Your mailbox comes with features like automated backup, mail filter rules, spam protection, email client auto-configuration, and more. You can also use a DNS configuration and make it your name server. All your incoming and outgoing messages go through TLSv1.2 encryption. You can also use Mail-in-a-Box to host mail for multiple users and different domain names. 


Mail-in-a-Box comes with the following features:

  • You can add multiple accounts.
  • It allows you to use a control panel feature to monitor and add aliases.
  • Mail-in-a-Box has an intuitive dashboard.
  • It has a spam filtering feature.
  • It has a flexible API that allows you to integrate with other applications. 

6. Docker mailserver

If you want to improve your customer services, thenDocker mailserver is the best mail-server for you. Business owners can use it to enhance client-business relationships. Docker mailserver comes with programs and protocols that make exchanging emails easy and fast, and you'll get access to tons of features.

Docker-mailserver offers business owners the server-side so that they get 100% control over emails. Meanwhile, clients can use a terminal via text-based software like Mozilla, Microsoft Outlook, etc. You can use Docker mailserver to forward, deliver, store and accept messages. Meanwhile, a specific piece of software will handle multiple tasks, to make it easy for you to do more than just sending and receiving emails. 


Docker-mailserver has the following features:  

  • It has a Mail User Agent feature that allows it to fetch emails from a mail server.
  • Docker-mailserver accepts Emails, then forward them to specific recipients. 
  • It has POP3, IMAP, SMTP functionalities.
  • It comes with an intuitive webmail interface. 
  • It has TLS encryption. 
  • You'll get a server-side mail filtering feature.
  • You can create, remove accounts, domains, and aliases.

7. Mailu

Another open-source email server you should consider is Mailu. While it is a simple tool, it comes with features that you can explore. It is a free solution, which means you can modify and configure without paying. We recommend Mailu for its easy-to-set-up; it only takes three to five commands to get you going. If you are stuck, there are tons of FAQs, videos, and text that can help you.   


Mailu boosts the following features:

  • Mailu has a standard email server that offers IMAP and IMAP+, SMTP, and Submission functionalities. 
  • You can create aliases, domain aliases, and custom routing.
  • It has a versatile administration interface that can handle multiple webmails. 
  • Users get auto-reply, auto-forward, and fetched accounts features. 
  • As an admin, you make announcements, send quotas, and delegate tasks. 
  • Mailu has a TLS encryption feature. So all your messages will be secure.  


Given business owners' challenges, you should always strive to minimize them instead of adding them up. Hence, you should get the right open source email server for your business. There are many open-source email servers, but it can be daunting to evaluate each. You will need to dedicate hours in order to do that, which most entrepreneurs don't have. 

An open-source email server like iRedMail is a good start. You can use it to send and receive emails without worrying that someone may hack your mailbox. But then, for a solution like iRedMail to work smoothly, there are certain things that you should get right. 

  • You need to make sure that you work with reputable IT specialists.
  • You need to configure it right.
  • You need to hire an IT specialist to test the functionalities regularly.
  • You need to know which features to use to grow your business.
  • Fix bugs. 

With hMailServer, you can also do more as well.  You can send out emails, filter your spam mail, share and collaborate on your documents, and manage your day-to-day calendar. But you only enjoy all those benefits once you configure it right. 

If you are still not sure which email-source email server to go for, reach out to us today. Our IT team is on standby to ensure that you get the best IT service. The sooner you do, the better for your business. 

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Oli SB
2 years ago

Open Web Systems offer open source, co-owned, surveillance-free email, office & collaborative tools, powered by renewable energy:

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James LePage
James LePage is the founder of Isotropic, a WordPress education company and digital agency. He is also the founder of, a venture backed startup bringing AI to WordPress creators.
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