NikaMail AlternativesMail Servers and other similar apps like NikaMail

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.

Exim is a message transfer agent (MTA) developed at the University of Cambridge for use on Unix systems connected to the Internet.

OpenSMTPD is a 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.

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.

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.

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.

In the default mode, it transmits a mail to an SMTP server (for example at a free mail provider) which takes care of further delivery.

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.

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.

MailerQ is a high performance Mail Transfer Agent (MTA) and a very fast SMTP server, designed to deliver large volumes of email messages at very high speeds. MailerQ is based on RabbitMQ AMQP.

BulkMTA is Commercial Mail Server Similar to PowerMTA. IP Rotation, DKIM, Sender / Receiver Rate limiting.

EmailSuccess, an advanced SMTP Server (MTA) built from the ground up to handle the most critical reliability, performance, security, and deliverability requirements.