Mail-in-a-Box vs Mailu (2026): which should you pick?
As of Nov 13, 2026, Mail-in-a-Box and Mailu share a 2.0 GPA, both are free, so the choice depends on whether you care more about features, where Mail-in-a-Box grades higher, or the free plan, where Mailu does.
Checked Nov 13, 2026 · graded Nov 13, 2026 by ToolGPA
They get the same grade on value for money, ease of use and platforms.
Price, platforms and features side by side. The table says where each price was read and when.
Mail-in-a-Box
Free script that turns a cloud server into your own mail server
Free
Which one is for you
Pick Mail-in-a-Box if
- Fits if you want your own mail on your own domain and can run a server
- Works for people who would rather run one script than configure ten programs
Look elsewhere if
- Skip it if you want a home connection to do it, since it needs a cloud server with a clean IP
- Skip it if you don't want to be the sysadmin
- Watch out: the page warns that other mail services may block or filter mail from your own server
- Watch out: it needs a dedicated fresh machine, and manual changes after install are overwritten
Pick Mailu if
- Fits if you want your own mail server in Docker and no groupware
- Works for admins who like plain compose files
Look elsewhere if
- Skip it if you want calendars and contacts, since the project says it avoids groupware
- Skip it if you don't want to run the server, DNS and backups
- Watch out: support is the community and contributors, and no paid plan exists
- Watch out: the docs are versioned, so make sure you read the one for your version
How we grade them
| 2.0GPAMail-in-a-BoxFair | 2.0GPAMailuFair | |
|---|---|---|
| Value for money | CThe software is free, but the guide puts a server at about $12 a month plus a domain at about $17 a year, which lands in the dearer end of the category. | CFree to run yourself, with a server to provide. The docs ask for 1 GB of memory, or 3 GB with antivirus. |
| Free plan and trial | CFree software that still needs a rented server running before anything works. | BThe whole server is free software, with no paid plan. You provide the machine and the upkeep. |
| Features | BMail server, webmail, automatic DNS and security records, spam filtering, backups, multiple users and domains. The listing shows no gap in the core job. | CStandard mail, webmail, an admin panel, spam filtering and security options. The project says it avoids groupware, so calendars and contacts are missing. |
| Ease of use | DYou install it on a fresh machine and act as the sysadmin, with help from a forum and chat room. | DYou run Docker or Kubernetes, DNS records and TLS yourself. |
| Platforms and integrations | CA web admin and webmail, with Roundcube, Nextcloud and Let's Encrypt. No apps of its own. | CWeb admin and webmail, with Docker, Kubernetes and Let's Encrypt. No apps of its own. |
| Best for | one script that makes a cloud server a mail server | a simple Docker mail server |
The GPA is the average of the five grades: an A is 4 points, an F is none. The full reasons are on each tool's page: Mail-in-a-Box and Mailu. How we grade
Price against what you get
Mail-in-a-Box has no paid plan and scores 2.0 out of 4 on features, ease of use and platforms. Mailu has no paid plan and scores 1.7.
Mail-in-a-Box scores higher for the same starting price. Of the other email apps on the chart, none scores higher than Mail-in-a-Box for less, and none scores higher than Mailu for less.
Features, ease of use and platforms, averaged
What paid plans start at, a month (each step along is roughly double) →
- The best score at each price
- Has a free plan
- No free plan
Where they differ
- Mail-in-a-Box also covers calendar.
- Mailu also covers dMARC.
In commonFree planWebOpen sourceSelf-hostableEmail client
At a glance
| Mail-in-a-Box | Mailu | |
|---|---|---|
| Pricing | Free | Free |
| Starts at | Free | Free |
| Free plan | The software is free; you pay for your own server and domain, which the setup guide puts at about $12 a month plus roughly $17 a year. | The whole mail server is free software; you provide the server, domain and upkeep. |
| Free trial | None listed | None listed |
| Web | ||
| Made by | Mail-in-a-Box project | Mailu project |
| Price read from | mailinabox.email | mailu.io |
| Checked | Nov 13, 2026 | Nov 13, 2026 |
Worth knowing
Mail-in-a-Box
- It cannot run on a home connection: it needs a cloud server with a clean IP, so the guide advises renting a virtual machine.
- It must be installed on a fresh machine dedicated to it, and manual changes after install are overwritten.
- The page warns that other mail services may block or spam-filter mail sent from your own server.
- You act as the system administrator and must fix issues yourself; help comes from a forum and chat room.
Mailu
- You provide and maintain the server, DNS records, TLS and backups yourself.
- The project says it aims to avoid groupware features, so calendars and contacts are not part of the core.
- Support is from the community and contributors; no paid plan appears on the site.
- The documentation is versioned, so check you are reading the version you run.
Key features
Mail-in-a-Box
- Webmail and mail server in one
- Includes Roundcube webmail and an IMAP and SMTP server for phones and desktop mail apps, with contacts and calendar sync.
- Automatic DNS and security records
- When the box acts as your nameserver it sets SPF, DKIM, DMARC and MTA-STS records, and can add DNSSEC with DANE.
- Control panel and API
- A web panel to add mail accounts, aliases and custom DNS records, run status checks and set up backups, also reachable over a REST API.
- Spam filtering and backups
- Spam filtering with greylisting, mail filter rules, TLS certificates from Let's Encrypt and automated backups to Amazon S3 and similar services.
- Multiple users and domains
- One box can host mail for several users and domain names, with simple static website hosting on the side.
Mailu
- Standard mail server
- IMAP, SMTP and submission with auto-configuration profiles for mail clients.
- Webmail and admin interface
- Includes web access to mail and an admin interface with global admins, per-domain delegation, announcements and quotas.
- User mail features
- Aliases, domain aliases, auto-reply, auto-forward, fetched accounts, ManageSieve and full-text search of attachments.
- Security options
- Enforced TLS, DANE, MTA-STS, Let's Encrypt, outgoing DKIM, an antivirus scanner and blocking of malicious attachments.
- Spam filtering
- Auto-learning, greylisting, DMARC and SPF checks and anti-spoofing.
- Compose and Kubernetes setups
- Documented Docker Compose and Kubernetes installs, a RESTful API and a command line for administration.
Plans
Mail-in-a-Box
Mail-in-a-Box$0
Free software. The setup guide estimates about $12 a month for the cloud server, plus a domain name at about $17 a year.
Mailu
Mailu$0
Free software you host yourself. The docs list 1 GB of memory without antivirus or 3 GB with it.
Common questions
Which is cheaper, Mail-in-a-Box or Mailu?
As of Nov 13, 2026, both Mail-in-a-Box and Mailu are free to use.
Which has a free plan, Mail-in-a-Box or Mailu?
As of Nov 13, 2026, both Mail-in-a-Box and Mailu have a free plan.
More comparisons
How this page was made
- The verdict at the top follows a fixed rule. When both tools are in the same category and either is in our top three for it, the verdict follows that ranking: the higher-placed tool is our pick. The top three weigh who each tool suits as well as its grades, so a pick can go against the GPA. Otherwise the page does not pick one and says which grades higher: the higher GPA first; on a tie, the one with a free plan, then the one that starts cheaper in dollars a month, counted the same way for both; if they are still level, what the choice depends on.
- The grades are our own, from each tool’s review or report card. The GPA is their average.
- Prices, plans and platforms come from each tool’s listing. The table above says where each price was read and when.
- The differences and the answers to the questions are worked out from those listings.