Open Source Windows Email Software
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Email Software for Windows
View 127 business solutionsBrowse free open source Email software and projects for Windows below. Use the toggles on the left to filter open source Email software by OS, license, language, programming language, and project status.
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Scrollout F1
An easy-to-use anti-spam email gateway
• Designed for Linux and Windows email system administrators, Scrollout F1 is an easy to use, already adjusted email firewall (gateway) offering free anti-spam and anti-virus protection aiming to secure existing email servers, old or new, such as Microsoft Exchange, Lotus Domino, Postfix, Exim, Sendmail, Qmail and others. • Built-in multilayer security levels make configuration effort equal to a car radio. • It combines simplicity with effective protection using powerful open source with additional set of rules & filters. • Available as 64bit: - ISO image (Internet connection required during installation) - install from scratch (Internet connection required during installation). • Minimum Requirements (for 5,000 messages/day): 1 GB of RAM 30 GB storage drive 1 Processor x86/AMD64 1 Ethernet x 1 IPv4 address UDP ports: 53 123 4500 6277 24441 TCP ports: 25 80 443 2703 -
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Anti-Spam SMTP Proxy Server
Anti-Spam SMTP Proxy Server implements multiple spam filters
The Anti-Spam SMTP Proxy (ASSP) Server project aims to create an open source platform-independent SMTP Proxy server which implements auto-whitelists, self learning Hidden-Markov-Model and/or Bayesian, Greylisting, DNSBL, DNSWL, URIBL, SPF, SRS, Backscatter, Virus scanning, attachment blocking, Senderbase and multiple other filter methods. Click 'Files' to download the professional version 2.8.1 build 24261. A linux(ubuntu 20.04 LTS) and a freeBSD 12.2 based ready to run OVA of ASSP V2 are also available for download. NOTICE: V1 development has been stopped at the end of 2014 (1.10.1 build 16060). Possibly there will be done some bugfixing in future. Please upgrade to V2, which is and will be actively maintained. -
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Windows MBox Viewer
Windows eml and mbox viewer.
Free Windows Mbox Viewer. Gain access to mbox archives, single eml or single Outlook messages. View attachments and export single mails in eml format. Access large mbox files such as Google Takeout or Mozilla Thunderbird Archives. Development of mbox viewer continues now at github: https://github.com/eneam/mboxviewer **NOTE**: Windows Defender may sometimes report incorrectly that mbox-viewer contains malware. Please report the case to the development. Development will ask Windows Security to update Windows Defender rules to resolve the issue. Last time the incorrect detection was corrected by Microsoft Security within few hours. User will need to run Windows Update to install the latest updated detection rules. -
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Ever wanted to get rid of Outlook ? DavMail is a POP/IMAP/SMTP/Caldav/Carddav/LDAP gateway allowing users to use any mail client with Exchange and Office 365, even from the internet through Outlook Web Access on any platform, tested on MacOSX, Linux and Windows
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PHPMailer
The classic email sending library for PHP
PHPMailer – A full-featured email creation and transfer class for PHP. Support for UTF-8 content and 8bit, base64, binary, and quoted-printable encodings. SMTP authentication with LOGIN, PLAIN, CRAM-MD5, and XOAUTH2 mechanisms over SMTPS and SMTP+STARTTLS transports. Validates email addresses automatically. Many PHP developers need to send email from their code. The only PHP function that supports this directly is mail(). However, it does not provide any assistance for making use of popular features such as encryption, authentication, HTML messages, and attachments. Formatting email correctly is surprisingly difficult. There are myriad overlapping (and conflicting) standards, requiring tight adherence to horribly complicated formatting and encoding rules – the vast majority of code that you'll find online that uses the mail() function directly is just plain wrong, if not unsafe! -
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GO Contact Sync Mod
Sync Outlook contacts and calendars with Google
Please install the latest version >4.0, because it uses the new Google People API. The Google Contacts API is now deprecated and is scheduled for sunset on June 15, 2021. GO Contact Sync Mod synchronizes your Microsoft Outlook contacts with your Google Mail address book, including pictures, categories and contact notes. It also syncs your Outlook Calendar Appointments on demand to Google Calendar. This Mod fork adds many enhancements and bug fixes to the obviously dead project 'Go Contact Sync'. Minimum requirement for GO Contact Sync Mod is .NET 4.7.2 and Windows 7 (32 or 64 bit). -
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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. -
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Outlook CalDav Synchronizer
Sync Outlook with Google, SOGo or any other CalDAV / CardDAV server
Free Outlook Plugin, which synchronizes events, tasks and contacts between Outlook and Google, SOGo, NextCloud, Horde or any other CalDAV or CardDAV server. Supported Outlook versions are 2021, 2019, 2016, 2013, 2010 and 2007 and Office 365 for Desktop. This project was initially developed as a master thesis project at the University of Applied Sciences Technikum Wien, Software Engineering Degree program. Outlook CalDav Synchronizer is Free and Open-Source Software (FOSS), still you can support the project by donating on Sourceforge or directly within the About dialog of our Plugin. Contact us for enterprise support at https://caldavsynchronizer.org/enterprise/contact -
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SquirrelMail is a PHP-based Web email client. It includes built-in pure PHP support for IMAP and SMTP, and renders all pages in pure HTML 4.0 for maximum compatibility across browsers. It has strong MIME support and a flexible plugin system.
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Mailspring
A faster, leaner email client and fork of Nylas Mail
Mailspring is a fast and lean mail client that’s a new version of Nylas Mail. It’s maintained by one of Nylas Mail’s original authors, with plenty of great features and enhancements such as a new C++ sync engine that allows it to use 50% less RAM. Heavy dependencies have also been removed and the package manager rewritten for even greater speed. Written in TypeScript with Electron and React, it is cross-platform (macOS, Windows and Linux) and designed to be easy to extend. -
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Blat - A Windows (32 & 64 bit) command line SMTP mailer. Use it to automatically eMail logs, the contents of a html FORM, or whatever else you need to send.
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theHarvester
E-mails, subdomains and names
theHarvester is a very simple to use, yet powerful and effective tool designed to be used in the early stages of a penetration test or red team engagement. Use it for open source intelligence (OSINT) gathering to help determine a company's external threat landscape on the internet. The tool gathers emails, names, subdomains, IPs and URLs using multiple public data sources. -
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ElectronMail
Unofficial ProtonMail Desktop App
ElectronMail is an Electron-based unofficial desktop client for ProtonMail. The app aims to provide enhanced desktop user experience enabling features that are not supported by the official in-browser web clients. It is written in TypeScript and uses Angular. The way of verifying that the installation packages attached to the releases have been assembled from the source code is being provided. The app works on Linux/OSX/Windows platforms. Binary installation packages. Offline access to the email messages (attachments content not stored locally, but emails body content). The local store feature enables storing your messages in the encrypted database.bin file (see FAQ for file purpose details). So the app allows you to view your messages offline, running full-text search against them, exporting them to EML/JSON files. etc. Enabled since v2.0.0 release. -
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Elastix
Unified Communications Server
Elastix is a software-based PBX powered by 3CX and based on Debian. An open-standards solution, Elastix is an easy to install and manage UC system compatible with popular IP phones, gateways and SIP trunks. Elastix is complete with unified communications features such as integrated WebRTC video conferencing, chat, presence and softphones and smartphone clients for Windows, Mac, iOS and Android. -
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Google Apps Manager
Command line management for Google G Suite
Google Apps Manager or GAM is a free and open source command line tool for Google G Suite Administrators that allows them to manage many aspects of their Google Apps Account quickly and easily. With GAM you can create and manage users, groups and domains; manage email, security and calendar settings; manage admins and organizations and many more. To use GAM Google Apps Business, Education, Partner or Government Edition is required. -
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PHPMailer
A full-featured email creation and transfer class for PHP
A PHP email creation and transport class featuring file attachments, SMTP servers, CCs, BCCs, HTML messages, word wrap, and more. Sends email via sendmail, PHP mail(), QMail, or with SMTP. PHPMailer is used by many popular PHP development frameworks and is one of the most popular email-generating and sending libraries in the world. This project is defunct here on sourceforge – it's now maintained on Github at https://github.com/PHPMailer/PHPMailer. Documentation is available at https://github.com/PHPMailer/PHPMailer/wiki -
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MsgViewer is email-viewer utility for .msg e-mail messages, implemented in pure Java. MsgViewer works on Windows/Linux/Mac Platforms. Also provides a java api to read mail messges (msg files) programmatically.
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Outlook Mail Merge Attachment is a script which can be used to add an attachment to an mail merge in Microsoft Outlook.
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phpList
Powerful Open Source Email Marketing app with analytics & segmentation
phpList delivers Open Source email marketing, including analytics, list segmentation, content personalisaton and bounce processing. Extensive technical features and a secure and stable codebase are the result of over 17 years of continuous development. Used in 95 countries, available in 20+ languages, and used to send 25 billion email campaigns last year. Deploy it with your own SMTP server, or get a free hosted account at http://phplist.com. -
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King Phisher
Phishing Campaign Toolkit
King Phisher is an open source tool that can simulate real world phishing attacks. It has an easy-to-use, flexible architecture that allows for full control over both emails and server content. It is useful for running awareness campaigns and training, and can only be used for legal applications when the explicit permission of the targeted organization has been obtained. -
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listmonk
High performance, self-hosted, newsletter and mailing list manager
Performance and features packed into a single binary. Manage millions of subscribers across many single and double opt-in lists with custom JSON attributes for each subscriber. Query and segment subscribers with SQL expressions. Use the super fast bulk importer (10k records per second) or use HTTP/JSON APIs or interact with the simple table schema to integrate external CRMs and subscriber databases. Visualize and compare campaign performance. Connect external visualization programs to the database easily with the simple table structure. Create powerful, dynamic e-mail templates with the Go templating language. Use template expressions, logic, and 100+ functions in subject lines and content. Write HTML e-mails in a WYSIWYG editor, Markdown, raw syntax-highlighted HTML, or just plain text. Highly configurable, multi-threaded, high-throughput multi-SMTP e-mail queues for super fast campaign delivery. -
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Tutanota
Open source email service with a strong focus on security and privacy
Tutanota is an open source email client focused on security and privacy. It is built with end-to-end encryption and 2FA, so you can be assured of utmost email security. Tutanota is always encrypted, so whether you’re using their secure webmail client, mobile apps or desktop clients, you can be sure to communicate securely. -
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PostfixAdmin is a Web Based Management tool created for Postfix. It is a PHP based application that handles Postfix Style Virtual Domains and Users that are stored in MySQL, PostgreSQL or SQLite
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Send SMTP email silently from command line (CLI), or a batch file using Exchange, Gmail, Hotmail, or Yahoo! Plus. Supports XML settings files, variables, or all settings explicitly from the command line. Now supporting Exit Codes for batch file use (will return "0" for successful delivery, or "1" for error delivering) - handle your batch file accordingly.
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Notifuse
Notifuse is an open-source & modern emailing platform
Notifuse is an open-source, modern, self-hosted emailing and communications platform designed to replace proprietary services like Mailchimp, Brevo, and Klaviyo with a self-managed solution. It’s built with a Go backend and a React frontend to offer both developer-friendly APIs and a user-centric visual interface with enterprise-grade capabilities such as campaign creation, subscriber segmentation, and detailed analytics. Notifuse supports both newsletters and transactional emails through a RESTful API, letting organizations maintain full control over their email infrastructure without expensive per-message pricing. The system includes a drag-and-drop MJML email builder, webhook integrations, and multi-provider support for SMTP services and cloud providers, while also tracking opens, clicks, and delivery performance in real time.
