The Best Mail Server Software in 2026
We researched mail server software using official websites, including pricing pages, plan tables, and product documentation. Rankings reflect each product’s core job, value for money, and verified features for operating self-hosted mail transfer, mailbox, and delivery infrastructure.
Our top picks
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Top ranked
Microsoft Exchange Online#1 of 349.3/10A Microsoft-centric hosted mailbox service with Outlook, archiving, compliance, and migration tools.
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Runner-up
Zimbra Collaboration#2 of 349.1/10A broad open-source suite for organizations that need email, collaboration, and deployment control.
Free plan
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Top-ranked free plan
Apache James#4 of 348.8/10A flexible self-hosted mail server with broad protocols, storage options, and deployment models.
Free plan
Advertiser disclosure: iTechGuides is reader-supported. Vendors can pay for top positions in our rankings and for a place on other products' pages, and we may earn a commission when you click some links. Bought places stand at the number bought; this page and our disclosure say so. Paying vendors may get a fuller, more detailed review from our editors, and that review can change their score. How we rank.
The full ranking 34 tools, best first
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Best forMicrosoft-centric business email
A Microsoft-centric hosted mailbox service with Outlook, archiving, compliance, and migration tools.
9.3/10★★★★★Visit Microsoft -
Best forFull-featured open-source collaboration mail
A broad open-source suite for organizations that need email, collaboration, and deployment control.
9.1/10★★★★★Visit Zimbra -
Best forHosted email plus productivity collaboration
A broad hosted email suite with collaboration, migration tools, and self-hosted deployment.
9.0/10★★★★☆Visit IceWarp -
Best forOpen-source, scalable mail infrastructure
A flexible self-hosted mail server with broad protocols, storage options, and deployment models.
- Antispam tools
- High availability
- IMAP/POP3 access
8.8/10★★★★☆Visit Apache James -
Best forWindows mail with perpetual licensing
A Windows-focused mail server with a free core edition and expandable paid tiers.
- Mobile sync
- Webmail interface
- Antispam tools
Free plan · 60-day trial Our MailEnable verdict → Visit MailEnableFor vendors Sponsor this spot · #5 · $59/mo →8.7/10★★★★☆Visit MailEnable -
Best forHigh-performance IMAP and POP3 backends
A focused, extensible mailbox backend for self-hosted Linux mail infrastructure.
- High availability
- IMAP/POP3 access
8.6/10★★★★☆Visit Dovecot -
Best forDocker-based mail and groupware deployments
A Dockerized mail and groupware suite for teams managing their own infrastructure.
8.5/10★★★★☆Visit mailcow -
Best forEnterprise mail with Domino application integration
A broad enterprise mail and application platform built around Domino integration.
- Mobile sync
- Webmail interface
- Antispam tools
8.4/10★★★★☆Visit HCL Domino -
Best forCommercial mail with webmail and groupware
A commercial mail server with webmail, groupware, migration, and deployment flexibility.
8.3/10★★★★☆Visit Axigen -
Best forSmall and mid-market collaborative teams
A broad mail and groupware server with flexible access and administrator controls.
8.2/10★★★★☆Visit Kerio Connect -
Best forAffordable self-hosted mail and groupware
Affordable self-hosted email with webmail, groupware, migration tools, and optional enterprise support.
8.1/10★★★★☆Visit iRedMail -
Best forWindows-based managed mail servers
A capable Windows mail server for organizations seeking on-premises or hosted Exchange alternatives.
- Mobile sync
- Webmail interface
- Antispam tools
8.0/10★★★★☆Visit MDaemon -
Best forTeams prioritizing collaboration alongside email
A flexible email and collaboration suite with cloud and self-hosted deployment options.
- Mobile sync
- Webmail interface
- High availability
7.9/10★★★★☆Visit Open-Xchange -
Best forOpen-source mail with collaboration tools
A broad open-source mail and collaboration suite for teams managing their own infrastructure.
7.8/10★★★★☆Visit Kolab -
Best forIntegrated mail for directory-managed teams
A broad self-hosted mail stack for teams that need integrated directory management.
- Mobile sync
- Webmail interface
- Antispam tools
7.7/10★★★★☆Visit Zentyal -
Best forAutomated personal or small-team mail hosting
A focused self-hosted mail stack for individuals and small teams managing their own email.
7.6/10★★★★☆Visit Mail-in-a-Box -
Best forWindows mail with a free entry tier
A broad Windows-focused mail server with a capable free tier and substantial paid licensing.
- Mobile sync
- Webmail interface
- Antispam tools
7.5/10★★★★☆Visit SmarterMail -
Best forSimple open-source mail with web administration
A free, open-source mail stack for teams managing their own email infrastructure.
- Webmail interface
- Antispam tools
- High availability
7.4/10★★★★☆Visit Mailu -
Best forEnterprise clustered messaging deployments
A clustered mail and collaboration server for organizations running private messaging infrastructure.
- Mobile sync
- Webmail interface
- Antispam tools
7.3/10★★★★☆Contact CommuniGate -
Best forFree self-hosted mail with built-in webmail
A free, broad self-hosted mail suite for Linux teams comfortable managing infrastructure.
- Mobile sync
- Webmail interface
- Antispam tools
7.2/10★★★★☆Visit Citadel -
Best forSmall Windows teams running their own mail
A free, open-source Windows mail server with configurable protocols, filtering, and storage.
7.1/10★★★★☆Visit hMailServer -
Best forHigh-volume outbound email delivery
A specialized MTA for organizations managing high-volume outbound delivery.
7.0/10★★★★☆Visit Bird -
Best forModern, low-cost open-source mail hosting
A capable self-hosted mail stack with collaboration services, clustering and a free Community edition.
- Mobile sync
- Antispam tools
- High availability
6.9/10★★★☆☆Visit Stalwart -
Best forWeb-managed open-source mail servers
A broad, free mail-management platform for teams running their own infrastructure.
6.8/10★★★☆☆Visit Modoboa -
Best forFlexible SMTP relay and delivery
A flexible SMTP foundation for administrators building self-hosted mail infrastructure.
- Antispam tools
- High availability
6.7/10★★★☆☆Visit Postfix -
Best forConfigurable SMTP and mail-routing deployments
A configurable, self-hosted MTA for administrators who need control over mail routing.
- Antispam tools
6.6/10★★★☆☆Visit Exim -
Best forMature, scalable IMAP infrastructure
A mature, scalable choice for organizations managing their own IMAP infrastructure.
- Antispam tools
- High availability
- IMAP/POP3 access
6.5/10★★★☆☆Visit Project Cyrus -
Best forMinimal legacy Linux mail transport
A free, narrow mail transport choice for Linux administrators maintaining legacy systems.
- IMAP/POP3 access
6.4/10★★★☆☆Visit qmail -
Best forExtensible SMTP filtering and routing
A focused, extensible SMTP server for custom filtering, routing, and delivery workflows.
- Antispam tools
6.3/10★★★☆☆Visit Haraka -
Best forMinimal secure SMTP relay infrastructure
A focused SMTP server for self-hosted mail routing, relay, and delivery.
6.2/10★★★☆☆Visit OpenSMTPD -
Best forOperators scripting SMTP routing and filtering
A free, open-source MTA for operators who need scripted SMTP routing and filtering.
6.1/10★★★☆☆Visit viridIT -
Best forSecurity-focused compact mail server
A free, security-focused mail server for compact Linux deployments.
- IMAP/POP3 access
6.0/10★★★☆☆Visit Maddy -
Best forTraditional Linux mail infrastructure
A broad self-hosted mail stack for teams managing Linux-based email systems.
- Webmail interface
- Antispam tools
- High availability
5.9/10★★★☆☆Visit Courier -
Best forFree self-hosted mail with optional support tiers
A broad self-hosted mail stack with a capable free edition and optional paid support.
5.8/10★★★☆☆Visit poste.io
No tools match those filters.
Compare at a glance
| # | Tool | Free plan | Paid from | License model | Score |
|---|---|---|---|---|---|
| 1 | Microsoft Exchange Online | No | 9.3 | ||
| 2 | Zimbra Collaboration | Yes | Free | 9.1 | |
| 3 | IceWarp | No | 9.0 | ||
| 4 | Apache James | Yes | Free | Open-source | 8.8 |
| 5 | MailEnable | Yes | Perpetual | 8.7 | |
| 6 | Dovecot | Yes | Free | Open-source | 8.6 |
| 7 | mailcow | Yes | Free | 8.5 | |
| 8 | HCL Domino | Subscription | 8.4 | ||
| 9 | Axigen | No | 8.3 | ||
| 10 | Kerio Connect | No | 8.2 | ||
| 11 | iRedMail | Yes | $10/user/yr | 8.1 | |
| 12 | MDaemon Messaging Server | No | Subscription | 8.0 | |
| 13 | Open-Xchange App Suite | Subscription | 7.9 | ||
| 14 | Kolab | Yes | Free | 7.8 | |
| 15 | Zentyal Mail Server | Yes | $230/yr | 7.7 | |
| 16 | Mail-in-a-Box | Yes | Free | 7.6 | |
| 17 | SmarterMail | Yes | $500/yr | Subscription | 7.5 |
| 18 | Mailu | Yes | Free | Open-source | 7.4 |
| 19 | CommuniGate Pro | 7.3 | |||
| 20 | Citadel | Yes | Free | Open-source | 7.2 |
| 21 | hMailServer | Yes | Free | 7.1 | |
| 22 | PowerMTA | 7.0 | |||
| 23 | Stalwart Mail Server | Yes | $1.09/user/yr | Open-source | 6.9 |
| 24 | Modoboa | Yes | Free | 6.8 | |
| 25 | Postfix | Free | Open-source | 6.7 | |
| 26 | Exim | Yes | Free | Open-source | 6.6 |
| 27 | Cyrus IMAP | Yes | Free | Open-source | 6.5 |
| 28 | qmail | Yes | Free | Open-source | 6.4 |
| 29 | Haraka | Yes | Free | Open-source | 6.3 |
| 30 | OpenSMTPD | Yes | Free | Open-source | 6.2 |
| 31 | vSMTP | Yes | Free | Open-source | 6.1 |
| 32 | Maddy Mail Server | Yes | Free | Open-source | 6.0 |
| 33 | Courier Mail Server | Yes | Free | Open-source | 5.9 |
| 34 | poste.io | Yes | $349/yr | 5.8 |
Head-to-head All 26 comparisons →
- Microsoft Exchange Online vs Zimbra Collaboration
- Microsoft Exchange Online vs Apache James
- Microsoft Exchange Online vs MailEnable
- Microsoft Exchange Online vs Dovecot
- Microsoft Exchange Online vs mailcow
- Microsoft Exchange Online vs HCL Domino
- Zimbra Collaboration vs Apache James
- Zimbra Collaboration vs MailEnable
- Zimbra Collaboration vs Dovecot
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How we rank mail server software
Every tool on this page was researched by iTechGuides Editors from its official website — pricing pages, plan tables and product documentation. We rank on how well each one does this category's core job, what the free or entry plan includes, and where it falls short. Where we have enough verified facts, the score out of 10 is a rubric — job fit, value and how much we could verify — shown with its breakdown on every tool's page; a tool we have not verified enough to score yet shows its rank without a number. Scores are re-checked when a product changes its plans. Read the full editorial policy, or submit a tool we missed.
Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026
Last updated · How we research and update