Browse free open source C++ Mail Transfer Agents and projects below. Use the toggles on the left to filter open source C++ Mail Transfer Agents by OS, license, language, programming language, and project status.

  • Easily Host LLMs and Web Apps on Cloud Run Icon
    Easily Host LLMs and Web Apps on Cloud Run

    Run everything from popular models with on-demand NVIDIA L4 GPUs to web apps without infrastructure management.

    Run frontend and backend services, batch jobs, host LLMs, and queue processing workloads without the need to manage infrastructure. Cloud Run gives you on-demand GPU access for hosting LLMs and running real-time AI—with 5-second cold starts and automatic scale-to-zero so you only pay for actual usage. New customers get $300 in free credit to start.
    Try Cloud Run Free
  • Go From AI Idea to AI App Fast Icon
    Go From AI Idea to AI App Fast

    One platform to build, fine-tune, and deploy ML models. No MLOps team required.

    Access Gemini 3 and 200+ models. Build chatbots, agents, or custom models with built-in monitoring and scaling.
    Try Free
  • 1
    E-MailRelay

    E-MailRelay

    SMTP email proxy and relay server

    E-MailRelay is a simple SMTP proxy and relay MTA, written in C++, for Linux and Windows. As a proxy all messages can be passed through a user-defined program, such as a spam-filter, which can drop, readdress, or edit messages as they pass through.
    Leader badge
    Downloads: 507 This Week
    Last Update:
    See Project
  • 2
    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, calendaring, and mailing list services.
    Leader badge
    Downloads: 182 This Week
    Last Update:
    See Project
  • 3
    hMailServer is a SMTP/POP3/IMAP server for Windows. Data is stored in MySQL/MSSQL database and is easily accessed using the COM library. Project info, trackers and downloads has moved to www.hmailserver.com.
    Leader badge
    Downloads: 39 This Week
    Last Update:
    See Project
  • 4
    MailArchiva is a powerful, full featured email archiving (email archiver) and compliance solution for mail systems such as Microsoft Exchange. It stores all incoming, outgoing and internal emails for long term storage. A web based user interface is avail
    Downloads: 4 This Week
    Last Update:
    See Project
  • Catch Bugs Before Your Customers Do Icon
    Catch Bugs Before Your Customers Do

    Real-time error alerts, performance insights, and anomaly detection across your full stack. Free 30-day trial.

    Move from alert to fix before users notice. AppSignal monitors errors, performance bottlenecks, host health, and uptime—all from one dashboard. Instant notifications on deployments, anomaly triggers for memory spikes or error surges, and seamless log management. Works out of the box with Rails, Django, Express, Phoenix, Next.js, and dozens more. Starts at $23/month with no hidden fees.
    Try AppSignal Free
  • 5
    YPOPs! is an application which emulates a POP3/SMTP mail server and provides free POP3 and SMTP access to Yahoo! Mail. It does not depend on Yahoo's POP3/SMTP mail server. You can use a mail client of your choice!
    Downloads: 3 This Week
    Last Update:
    See Project
  • 6
    A small, fast, secure, anti-spam SMTP mail server (MTA). Delivery to mbox files and Maildirs supported. qwik-smtpd supports RBL, relay checking, raw/custom message handlers, and more. Custom authentication via checkpassword and a qmail-compatible configu
    Downloads: 6 This Week
    Last Update:
    See Project
  • 7
    DSN Support for Exim. This patch allows Exim 4.xx to support the sending of email Delivery Status Notifications. From Exim 4.83 onwards DSN is now included as standard (based on this patch). dsn_process was a removed option of this standard inclusion and so the patches after 4.76 will re-enable that functionality and provide a binary with the same options / configurations as previously.
    Downloads: 1 This Week
    Last Update:
    See Project
  • 8
    jwSMTP, Send email programmatically (C++ code/lib). Linux, BSD, Windows etc. Attachments, Multiple recipients, Cc/Bcc recipients supported. MX lookup or send to an SMTP server direct. LOGIN and PLAIN authentication now supported. Html or plain text forma
    Downloads: 1 This Week
    Last Update:
    See Project
  • 9
    ASMMS -- Anonymous SMTP Mail Message Sender ... is an simple mta, written in C, for sending mails through mail servers, which have no authentication (AUTH). It should work on nearly all POSIX systems, tested only with SunOS, Linux and HPUX.
    Downloads: 0 This Week
    Last Update:
    See Project
  • $300 in Free Credit for Your Google Cloud Projects Icon
    $300 in Free Credit for Your Google Cloud Projects

    Build, test, and explore on Google Cloud with $300 in free credit. No hidden charges. No surprise bills.

    Launch your next project with $300 in free Google Cloud credit—no hidden charges. Test, build, and deploy without risk. Use your credit across the Google Cloud platform to find what works best for your needs. After your credits are used, continue building with free monthly usage products. Only pay when you're ready to scale. Sign up in minutes and start exploring.
    Start Free Trial
  • 10
    Amail is a mail deamon with web interface. Writen in PHP and C++.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 11
    This project aims to be a personal data storage and administration system. It will be an advanced system for information and electronic mail management. The server will be accessible to any IMAPv4 compatible mail client.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 12
    E-mail greylisting system implemented as a freestanding executable suitable for use with Exim 4, using MySQL database back-end.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 13

    CRM114 MILTER

    CRM114 milter for sendmail

    This is a milter which scans emails with CRM114
    Downloads: 0 This Week
    Last Update:
    See Project
  • 14
    IMAP protocol implementation in C++
    Downloads: 0 This Week
    Last Update:
    See Project
  • 15
    Emdras is a Mail Transport Agent / Mail server for any Win32 platform. It has a SMTP client, SMTP server, POP3 server and POP3 client.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 16
    F1-Mailer : A simple Mailer in command line for windows users with MIME format. F1-Meiler allows people sending emails via SMTP relaying servers on the Web, with mail attachement. File attachment and email dating support. A tool to begin in Web/SMTP.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 17
    Modular EMail Server with features to support SMTP-after-POP,Anti-Virus filter by using popular AV-Scanners,IMAP,POP3,SSL,ODMR,SASL and has an easy configuration. (SMTP,ODMR,IMAP,POP3,SASL,CHUNKING,BINARYMIME,PAM)
    Downloads: 0 This Week
    Last Update:
    See Project
  • 18
    A proxy server for gmail, that enables you to fetch your gmails using IMAP or POP3, and send mails by SMTP via your gmail account.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 19
    Iceberg is another MTA based on CORBA like middleware called ICE from zeroc.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 20
    ImportArgo is a utility to import configuration and settings from Argosoft Mail Server to the open-source hMailServer
    Downloads: 0 This Week
    Last Update:
    See Project
  • 21
    A C# wrapper library for using MAPI (Messaging API) on Pocket PCs and Smartphones written 99% in C#. Allows for viewing and sending emails and SMS messages and their associated properties.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 22
    Mailafar is a mail server designed for use in difficult communication environments providing a full set of Internet email protocols, web mail, web admin, dial-in and wireless LAN access control. It will run on Linux, FreeBSD and Windows.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 23
    This program rapidly delivers bulletins by linking them to a single bulletin file. This saves heaps of disk space and is >100 times faster than regular delivery.
    Downloads: 0 This Week
    Last Update:
    See Project
  • 24
    Moxy is a transparent mail proxy. With Moxy, mail servers can listen for and receive mail on non standard ports, users retain complete control over their servers, no need to update DNS MX record with IP changes, bandwidth logged per domain or email
    Downloads: 0 This Week
    Last Update:
    See Project
  • 25
    Openminds-Solutions is a project intended to group a set of developments done by our team accros our evolution.
    Downloads: 0 This Week
    Last Update:
    See Project
  • Previous
  • You're on page 1
  • 2
  • Next
MongoDB Logo MongoDB