Email Clients for Windows

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Browse free open source Email Clients and projects for Windows below. Use the toggles on the left to filter open source Email Clients by OS, license, language, programming language, and project status.

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  • 1
    Windows MBox Viewer

    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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    Downloads: 1,276 This Week
    Last Update:
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  • 2
    SquirrelMail
    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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    Downloads: 197 This Week
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  • 3
    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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    Downloads: 109 This Week
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  • 4
    PHPMailer

    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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    Downloads: 71 This Week
    Last Update:
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  • 5
    Cypht

    Cypht

    Lightweight Open Source webmail written in PHP and JavaScript

    All your E-mail, from all your accounts, in one place. Cypht is not your father's webmail. Unless you are one of my daughters, in which case it is your father's webmail. Cypht is like a news reader, but for E-mail. Cypht does not replace your existing accounts - it combines them into one. And it's also a news reader. The driving force behind Cypht development is to provide combined views for multiple accounts, but it's also a standard E-mail client that lets you browse and manage IMAP folders and send outbound messages with SMTP. Cypht is an application built entirely of plugins, or as we call them, module sets (which is obviously way cooler sounding than plugins), that are executed by the framework. Modules provide a flexible way to add new features or customize the program without hacking the code. Cypht is Open Source (LGPL V2), and written in PHP and JavaScript.
    Downloads: 12 This Week
    Last Update:
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  • 6
    Proton Mail Bridge

    Proton Mail Bridge

    Proton Mail Bridge application

    Proton Mail Bridge is a desktop application that runs in the background on Windows, macOS, and Linux to enable users to access their Proton Mail encrypted email accounts with traditional email clients like Outlook, Thunderbird, Apple Mail, and others via local IMAP/SMTP servers. Because standard IMAP cannot natively decrypt end-to-end encrypted messages, Bridge acts as a translator that downloads encrypted mail, decrypts it locally, and serves it to your preferred mail client over a local server, while encrypting outgoing messages before they’re sent to Proton’s servers. It provides a seamless integration layer for users who need offline support, familiar local client workflows, or tighter integration with desktop tools while preserving Proton’s zero-access encryption model. The Bridge app continues running even when its GUI is closed so that mail clients can remain connected and synchronized, and it supports automatic startup and robust credential handling via secure storage.
    Downloads: 12 This Week
    Last Update:
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  • 7
    Mailspring

    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.
    Downloads: 11 This Week
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  • 8

    HERMES Mail

    The cult-favourite eMail client formerly known as Qualcomm Eudora

    eMail traffic is on the rise. With over 100 man-years of development time behind it and a clean, intuitive interface that makes handling messages a breeze, Hermes Messenger (formerly known as QUALCOMM Eudora) is more than a way to send and receive mail: it's a powerful management tool with features to increase your productivity and enhance your communications. It is the best eMail program for people who get lots of it. If you're not yet one of them, you soon will be. Take control of your eMail before it takes control of you! Hermes provides industrial-strength communication, free of ads and free of cost.
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    Downloads: 50 This Week
    Last Update:
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  • 9
    PoptrayU

    PoptrayU

    Email Notifier For Windows

    This email notifier sits in your system tray and pops up a notification when new messages arrive. Preview your email before downloading it to your mail client or launching webmail applications. Create rules to delete or change the priority of messages. This program builds upon the open source PopTray mail notifier adding many new features including Windows Vista/7/8/10 support, UTF-8 and unicode support, HTML Preview, IMAP support, TLS & SASL support, etc.
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    Downloads: 30 This Week
    Last Update:
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  • 10
    Tutanota

    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.
    Downloads: 5 This Week
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  • 11
    Trojitá, a Qt IMAP e-mail client
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    Downloads: 61 This Week
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  • 12
    Magic Mail Monitor3 - Windows mail checker with multiple mailboxes support, ability to preview and delete messages. Based on original code of Magic Mail Monitor from Valeriy Ovechkin.
    Downloads: 13 This Week
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  • 13
    PopTray is a mail notifier written in Delphi for the Windows platform. It sits in your tray notification area and check mail from multiple accounts on a timer interval. Preview, Delete, Rules, Plug-ins and translated into more than 30 languages.
    Downloads: 14 This Week
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  • 14
    NOCC
    NOCC is a simple and fast Webmail client which can handle POP3 and IMAP mailboxes and sends email via SMTP. It is written with PHP, has low requirements (no database, frames). Features multi-language support, MIME attachments, displays HTML messages. The installation guide comes with the source code: https://sourceforge.net/p/nocc/code/HEAD/tree/trunk/webmail/docs/INSTALL If you encounter problems or bugs you can always try the current HEAD version: https://sourceforge.net/p/nocc/code/HEAD/tarball?path= Questions, bug reports or support requests are very welcome: https://sourceforge.net/p/nocc/_list/tickets Alternative source code repository: https://github.com/oheil/NOCC
    Downloads: 5 This Week
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  • 15
    IGSuite - Integrated Groupware Suite

    IGSuite - Integrated Groupware Suite

    IGSuite is a web-ajax-based Integrated Groupware Suite

    IGSuite is a web-based Integrated Groupware Suite oriented to be a CRM solution. In the Suite you can find: IGWebMail, IGCalendar, IGContacts, IGArchive, IGWiki, IGTodo, IGChat, Projects, IGFax an HylaFax client, IGFileManager, IGMsg and many other.
    Downloads: 5 This Week
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  • 16
    It is an email sender. This software can send your mass marketing bulk email to unlimited mailing list. The program can send via SMTP server, MAPI, or delivers e-mail directly without ISP's mail system. Also includes flexible address filters and rules.
    Downloads: 3 This Week
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  • 17
    Mail Notifier

    Mail Notifier

    Mail Notifer for Windows

    Mail Notifier is free, modern email notifier with the latest user interface trends for Windows 10/11. It supports multiple accounts and IMAP/POP3 protocols. Enjoy customizable notifications, message previews, and more, all in 34 languages! For more details, please refer to the readme.txt file (Files tab, description below). Note: Gmail support is currently unavailable due to verification requirements by Google. Note: Outlook.com support is currently unavailable due to moving to OAuth2 authentication from login/password at Outlook servers.
    Downloads: 8 This Week
    Last Update:
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  • 18
    MultiMail Offline Reader
    MultiMail is an offline mail packet reader for Unix and other systems. It currently supports the Blue Wave, QWK, OMEN, OPX and SOUP formats. It has a full screen, color user interface, built with the curses library.
    Downloads: 4 This Week
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  • 19
    Sophisticated mail sender with a lot of settings. You can set number of email to every recipient. Program put every email random (random choice from file) sender, subject and text. You can put a enclosure too.
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    Downloads: 6 This Week
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  • 20
    EGroupware Enterprise Collaboration
    EGroupware has moved to Github, please find all our downloads there: https://github.com/EGroupware/egroupware/releases EGroupware is a multi-user, web-based groupware suite. Currently available modules include: email, addressbook, calendar, infolog (notes, to-do's, phone calls), content management, wiki, project management, tracker, timesheet, knowledge base, CalDAV/CardDAV
    Downloads: 1 This Week
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  • 21

    MorphyMail Free Email Marketer

    Create, send and track Unlimited bulk emails for Free

    Desktop software for windows to create, send and track unlimited bulk emails for lifetime for free. Includes 500 email templates , automated bounce and subscription processing, spam checker, WYSIWYG HTML editor, google analytics and social media integration, automated delivery tracking to track opens , clicks and geolocation of recipients, multithreaded engine for fast delivery of emails, website forms integration, scheduled mailing and much more features. It is a 100% free software to send unlimited bulk emails for lifetime.
    Downloads: 1 This Week
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  • 22
    GoldBug - Encrypted Communications

    GoldBug - Encrypted Communications

    Chat Messenger. E-Mail-Client. Websearch. Filetransfer.

    GoldBug is a decentralized & secure communication suite that offers an integrated e-mail client, an instant messenger & a file transfer. Also included is an URL-RSS-DB & a p2p web search. Current vers. w/ McEliece Algorithm. GoldBug has been 2013 - 2023 ten years just another Graphical User Interface of the Spot-On Encryption Suite. Main GUI features: Minimal & colorful Interface with Tabs in the East. Microsoft & Qt MinGW deprecated Win32 & for Compiling: ● https://sourceforge.net/p/goldbug/wiki/compiling As Spot-On implemented the minimal GB-concept & Nuvola Icons, GoldBug has now been fully integrated into Spot-On Win64: Just choose Tabs at East & Mini-View in Options - w/ Nuvola Icons of course! Voilá! & Many Thanks, Pro-Files can be found archived at ● current source: https://github.com/textbrowser/spot-on ● EN Manual: https://www.amazon.com/dp/3749435065 ● DE: https://compendio.github.io/goldbug-manual-de/ ● Study: https://www.amazon.com/asin/dp/3750408971
    Downloads: 4 This Week
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  • 23
    Emexis-webmail

    Emexis-webmail

    Webmail open-source in php base on Squiremail

    emexis-webmail is a skin for the well-known Squirremail The intention of this project is to create more friendly interface for the End User If you have any problem or you would like share your thinking about the Emexis-Webmail, access our group on google. You can also send a mail for bborges@brc.com.br. http://groups.google.com/group/emexis-webmail
    Downloads: 2 This Week
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  • 24
    AfterLogic WebMail Lite 7
    AfterLogic WebMail Lite PHP is a free AJAX webmail application. Users can receive, view, manage, compose, and send email through web interface (IMAP and SMTP supported). Source code included.
    Downloads: 1 This Week
    Last Update:
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  • 25
    Mailbird

    Mailbird

    All your email accounts in one place.

    Mailbird is an intuitive email management application that brings all your email accounts together in one place, making it easier to manage your emails across both Windows and Mac devices. With a single license, Mailbird enables users to track emails, organize their inboxes, and integrate various third-party apps like Slack, Google Calendar, and Dropbox for enhanced productivity. Key features include AI-powered email drafting, customizable workspaces, and the ability to track email opens. Mailbird also offers the ability to block unwanted senders and unsubscribe from lists directly from the app. With over 4 million users worldwide, Mailbird has become a popular choice for professionals and businesses looking to enhance their email experience.
    Downloads: 3 This Week
    Last Update:
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