OpenSMTPD Alternatives

OpenSMTPD is described as 'FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with some additional standard extensions. It allows ordinary machines to exchange e-mails with other systems speaking the SMTP protocol' and is an app in the office & productivity category. There are more than 10 alternatives to OpenSMTPD for a variety of platforms, including Linux, Mac, Windows, BSD and Self-Hosted solutions. The best alternative is Postfix, which is both free and Open Source. Other great apps like OpenSMTPD are Sendmail, sSMTP, Exim and Inbucket.

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OpenSMTPD

Free • Open Source

Linux
BSD
Self-Hosted

OpenSMTPD is a FREE implementation of the server-side SMTP protocol as defined by RFC 5321, with some additional standard...

Learn more about OpenSMTPD

Postfix
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Free • Open Source
Mail Server
Mac
Linux
23 alternatives to Postfix
Postfix is a mail transfer agent (MTA) that routes and delivers electronic mail. It attempts to be fast, easy to administer, and secure. The software is also known by its former names VMailer and IBM Secure Mailer.

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Sendmail
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Free • Open Source
Mail Server
Mac
Linux
27 alternatives to Sendmail
Sendmail is a general purpose internetwork email routing facility that supports many kinds of transfer and delivery methods, including the Simple Mail Transfer Protocol (SMTP) used for email transport over the Internet.
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Sendmail Features
SMTP Support
sSMTP
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Free • Open Source
Linux
19 alternatives to sSMTP
sSMTP is a simple MTA to deliver mail from a computer to a mail server. sSMTP is simple and lightweight, there are no daemons or anything hogging up CPU; Just sSMTP. Unlike Exim4, sSMTP does not receive mail, expand aliases, or manage a queue.
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sSMTP Features
Support for NodeJS
SMTP Support
Discontinued
The last update was in 2013.
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Exim
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No
Free • Open Source
Mail Server
Mac
Linux
16 alternatives to Exim
Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.
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Exim Features
SMTP Support
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Inbucket
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Free • Open Source
Mac
Windows
Linux
6 alternatives to Inbucket
Need to test your webapps outbound emails with Mailinator but stuck behind a firewall? Want to keep the new application you are developing secret until it’s time to release it? Need to validate that emails go out as part of your integration test suite?
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Inbucket Features
POP3 Support
SMTP Support
REST API
Courier-MTA
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No
Free • Open Source
Mail Server
Mac
Linux
BSD
Self-Hosted
12 alternatives to Courier-MTA
The Courier mail transfer agent (MTA) is an integrated mail/groupware server based on open commodity protocols, such as ESMTP, IMAP, POP3, LDAP, SSL, and HTTP. Courier provides ESMTP, IMAP, POP3, webmail, and mailing list services within a single, consistent, framework.
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Courier-MTA Features
1. Mail FilteringCourier-MTA classifies email messages according to specified criteria, allowing you to automatically recognize fraudulent or spam messages.
SMTP Support
IMAP Support
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Dragonfly Mail Agent
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No
Free • Open Source
Linux
BSD
7 alternatives to Dragonfly Mail Agent
A small Mail Transport Agent (MTA), designed for home and office use. Part of DragonFly BSD , it accepts mails from locally installed Mail User Agents (MUA) and delivers the mails either locally or to a remote destination.
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Dragonfly Mail Agent Features
SMTP Support
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Microsoft SMTP Server
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Paid • Proprietary
Windows
13 alternatives to Microsoft SMTP Server
Configure SMTP e-mail in IIS when you want to deliver e-mail messages from your site. Mail can be delivered immediately or it can be delivered to a file location on disk where it can be retrieved for delivery later.
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Microsoft SMTP Server Features
Exchange
Email Forwarding
SMTP Support
Haraka
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Yes
No
Free • Open Source
Self-Hosted
Node.JS
6 alternatives to Haraka
Haraka is an open source SMTP server written in Node.js which provides extremely high performance coupled with a flexible plugin system allowing Javascript programmers full access to change the behaviour of the server.
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Haraka Features
Support for Javascript
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NikaMail
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No
Free • Open Source
Mail Server
Mac
Linux
14 alternatives to NikaMail
NikaMail is a portable, extendable, zero-config email server. It is designed to perform automation tasks, provide access to mailboxes (port 110), serve as a mail transfer agent (port 587) and mail exchange service (port 25). NikaMail supports TLS.
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NikaMail Features
POP3 Support
Exchange email