Mailu vs Stalwart Mail Server (2026): which should you pick?
As of Nov 13, 2026, Stalwart Mail Server grades higher than Mailu: 2.2 against 2.0 out of 4.0.
Checked Nov 13, 2026 · graded Nov 13, 2026 by ToolGPA
Stalwart Mail Server grades higher on features. They get the same grade on value for money, the free plan, ease of use and platforms.
Price, platforms and features side by side. The table says where each price was read and when.
Stalwart Mail Server
Open-source mail and collaboration server written in Rust
Which one is for you
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
Pick Stalwart Mail Server if
- Fits if you run mail for a company and want a modern single-binary server
- Works for admins who want multi-tenancy and are fine paying per mailbox
Look elsewhere if
- Skip it if you want a hosted service, as the cloud edition is listed for 2027
- Not for you if you have fewer than 25 mailboxes on Enterprise
- Skip it if you don't want to run and update a server
- Watch out: the monthly-billing rate isn't shown and prices switch between euros and dollars
How we grade them
| 2.0GPAMailuFair | 2.2GPAStalwart Mail ServerFair | |
|---|---|---|
| Value for money | CFree to run yourself, with a server to provide. The docs ask for 1 GB of memory, or 3 GB with antivirus. | CCommunity is free if you host it. Enterprise is $2.40 a mailbox a year, but you pay for at least 25 mailboxes, which is $60 a year. |
| Free plan and trial | BThe whole server is free software, with no paid plan. You provide the machine and the upkeep. | BThe full server is free to run under the AGPL, plus a 30-day trial of Enterprise. You need your own server. |
| Features | CStandard mail, webmail, an admin panel, spam filtering and security options. The project says it avoids groupware, so calendars and contacts are missing. | BMail and collaboration in one server, with spam filtering, encryption at rest and clustering. The listing shows no gap in the job. |
| Ease of use | DYou run Docker or Kubernetes, DNS records and TLS yourself. | DYou install, configure and update the server yourself, in either edition. |
| Platforms and integrations | CWeb admin and webmail, with Docker, Kubernetes and Let's Encrypt. No apps of its own. | CA web admin and standard protocols, with Sieve, LDAP and OpenID Connect. No apps of its own. |
| Best for | a simple Docker mail server | a mail and collaboration server in Rust |
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: Mailu and Stalwart Mail Server. How we grade
Price against what you get
Mailu has no paid plan and scores 1.7 out of 4 on features, ease of use and platforms. Stalwart Mail Server starts at $0.20 a month when paid by the year and scores 2.0.
Stalwart Mail Server scores higher, and starts $0.20 a month higher: the question is whether the extra is worth that to you. Of the other email apps on the chart, none scores higher than Mailu for less, and 12 score higher than Stalwart Mail Server 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
- Stalwart Mail Server also covers calendar and file sharing.
At a glance
| Mailu | Stalwart Mail Server | |
|---|---|---|
| Pricing | Free | Free plan |
| Starts at | Free | $2.40 per mailbox / year, billed annually (25-mailbox minimum) |
| Free plan | The whole mail server is free software; you provide the server, domain and upkeep. | Community edition: the full mail server under AGPL-3.0, free to run on your own infrastructure. |
| Free trial | None listed | 30-day trial of the Enterprise edition with full access to Enterprise features. |
| Web | ||
| Made by | Mailu project | Stalwart Labs |
| Price read from | mailu.io | stalw.art |
| Checked | Nov 13, 2026 | Nov 13, 2026 |
Worth knowing
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.
Stalwart Mail Server
- Prices are shown in euros or dollars through a toggle; billing can be annual or monthly, and the monthly rate is not shown.
- Enterprise has a 25-mailbox minimum, and deployments above 100,000 mailboxes are quoted.
- Stalwart Enterprise Cloud, the hosted service, is listed as available in 2027, with interest registration only.
- You run and update the server yourself in either edition.
Key features
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.
Stalwart Mail Server
- Mail and collaboration in one server
- JMAP, IMAP and POP3 for mail, SMTP for delivery, plus calendars, contacts and file storage over CalDAV, CardDAV and WebDAV.
- Built-in spam and phishing filtering
- A statistical classifier, public blocklists, sender reputation and AI-driven analysis run inside the server.
- Sender authentication and transport security
- Handles DKIM, SPF, DMARC and ARC, plus DANE, MTA-STS and TLS reporting, with automatic certificate renewal over ACME.
- Encryption at rest
- Mailboxes can be encrypted with the user's own S/MIME certificate or OpenPGP key.
- Clustering
- Runs as a single node or as a cluster across regions.
- Enterprise multi-tenancy
- The Enterprise edition isolates tenants with their own accounts, domains, quotas and branding, for hosting many customers.
Plans
Mailu
Mailu$0
Free software you host yourself. The docs list 1 GB of memory without antivirus or 3 GB with it.
Stalwart Mail Server
Community$0
Free AGPL-3.0 edition you host yourself, with the same protocols and core mail features as Enterprise.
Enterprise$2.40
per mailbox / year, billed annually, 25 to 499 mailboxes
Adds multi-tenancy, branding, archiving and telemetry. Rate falls to $2.04 at 500 and $1.74 at 1,000 mailboxes.
Common questions
Which is cheaper, Mailu or Stalwart Mail Server?
As of Nov 13, 2026, Mailu is cheaper to start with: it is free, against $0.20 a month when paid by the year for Stalwart Mail Server. Mailu is free, and Stalwart Mail Server starts at $2.40 per mailbox / year, billed annually (25-mailbox minimum).
Which has a free plan, Mailu or Stalwart Mail Server?
As of Nov 13, 2026, both Mailu and Stalwart Mail Server 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.