List of mail server software

This is a list of mail server software: mail transfer agents, mail delivery agents, and other computer software which provide e-mail.

Product statistics

All such figures are necessarily estimates because data about mail server share is difficult to obtain; there are few reliable primary sources—and no agreed methodologies for its collection.

Surveys probing Internet-exposed systems typically attempt to identify systems via their banner, or other identifying features. As of December 2023^[update], Postfix and exim appeared to be the overwhelming leaders in mail server types, with greater than 92% share between them, having come to prominence before 2010 in each case. While such methods are effective at identifying mail server share for receiving systems, most large-scale sending environments are not listening for traffic on the public internet and will not be counted using such methodologies.

SMTP

agorum core
Apache James
Axigen
Chasquid
Citadel
CommuniGate Pro
Courier
Eudora Internet Mail Server
Exim
FirstClass
Gordano Messaging Suite
Halon Engage & Protect
Haraka
HCL Domino / formerly IBM Lotus Domino
hMailServer
IceWarp Mail Server (formerly Merak Mail Server)
Ipswitch IMail Server
Ironport
Kerio Connect
Koukan
MailEnable
Mailtraq
MDaemon
Mercury Mail Transport System
MeTA1
Microsoft Exchange Server
MMDF
Novell NetMail
OpenSMTPD
Openwave Systems
Open-Xchange
Oracle Beehive
Oracle Communications Messaging Server
Poste.io
Postfix
PowerMTA
qmail
qpsmtpd
RaidenMAILD
Scalix
Sendmail
Smail
SparkEngine
Stalwart Mail Server
Sun Java System
Surgemail
vSMTP
WinGate
WinWebMail
XMail
Zimbra
ZMailer

POP/IMAP

agorum core
Apache James
Axigen
Bongo
Citadel/UX
CommuniGate Pro
Courier Mail Server
Cyrus IMAP server
Dovecot
Eudora Internet Mail Server
FirstClass
Gordano Messaging Suite
hMailServer
IceWarp Mail Server (formerly Merak Mail Server)
Ipswitch IMail Server
HCL Domino / formerly IBM Lotus Domino
Kerio Connect
Kopano
Mailtraq
MDaemon
Mercury Mail Transport System
Microsoft Exchange Server
Mirapoint Email Appliance
Novell GroupWise
Novell NetMail
Open-Xchange
Oracle Beehive
Oracle Communications Messaging Server
Qpopper
RaidenMAILD
Stalwart Mail Server
UW IMAP
WinGate
WinWebMail
Zarafa
Zentyal
Zimbra

JMAP

Apache James
Cyrus IMAP server
Stalwart Mail server

Mail filtering

Anti-Spam SMTP Proxy
Axigen
Bogofilter
Clearswift Secure Email Gateway
DSPAM
fdm
Gordano Messaging Suite
IceWarp Mail Server
Libraesva
MailChannels
MailScanner
Mailtraq
MDaemon
Mimecast
MIMEDefang
procmail
Proxmox Mail Gateway
PureMessage
Rspamd
SurfControl
SpamAssassin
Thexyz
WinGate
Webroot
Proofpoint, Inc.

Mail server packages

docker-mailserver
iRedmail
Maddy Mail Server
Mail-in-a-Box
Mailcow
Mailu
Modoboa
Mox
Postal
Poste.io
Stalwart Mail Server

Tools

Swaks (Swiss Army Knife for SMTP)