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
    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: 756 This Week
    Last Update:
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  • 2
    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
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    Downloads: 29 This Week
    Last Update:
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  • 3
    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: 6 This Week
    Last Update:
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  • 4
    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: 16 This Week
    Last Update:
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  • 5
    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
    Last Update:
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  • 6
    mailredirect

    mailredirect

    Allow to redirect (a.k.a. "remail") mail messages to other recipients

    The Mailredirect extension for Mozilla Thunderbird and Mozilla SeaMonkey adds the ability to redirect one or more email messages to one or more recipients. The feature of email redirecting is also known as remailing or resending. The extension is an answer for https://bugzil.la/12916
    Downloads: 3 This Week
    Last Update:
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  • 7
    The OpenP2M is a software that lets you store and share files on your email account.
    Downloads: 2 This Week
    Last Update:
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  • 8
    RainLoop Webmail (PHP)

    RainLoop Webmail (PHP)

    Simple, modern & fast web-based email client

    Modest system requirements, decent performance, simple installation and upgrade, no database required - all these make RainLoop Webmail a perfect choice for your email solution.
    Downloads: 2 This Week
    Last Update:
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  • 9
    AfterLogic WebMail Lite .NET
    Free and easy-to-use webmail script with AJAX interface. Supports POP3/IMAP accounts, SMTP, SSL. Users can check and send mail, use address book. Skins, non-English languages, UTF-8. MS SQL/MySQL/MS Access backends supported.
    Downloads: 1 This Week
    Last Update:
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    With up to 25k MAUs and unlimited Okta connections, our Free Plan lets you focus on what you do best—building great apps.

    You asked, we delivered! Auth0 is excited to expand our Free and Paid plans to include more options so you can focus on building, deploying, and scaling applications without having to worry about your security. Auth0 now, thank yourself later.
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  • 10
    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: 0 This Week
    Last Update:
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  • 11
    Archive This for Thunderbird
    "Archive This" is an add-on for the Thunderbird email client that provides shortcuts for filing messages into folders rapidly and efficiently.
    Downloads: 0 This Week
    Last Update:
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  • 12
    Gmail Attachment Forward Tool Let user forward many attachment mail which already in your mailbox at same time. Very easy to move many file to other mail box.
    Downloads: 0 This Week
    Last Update:
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  • 13
    LED Lens Information Network
    Downloads: 0 This Week
    Last Update:
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  • 14
    Roundcube Webmail

    Roundcube Webmail

    Free and open source webmail software

    Roundcube Webmail is a browser-based, multilingual IMAP client with an application-like user interface. Roundcube provides the full functionality you'd expect from an email client, including MIME support, address book, folder manipulation, message searching, and spell check. Roundcube is written in PHP and JavaScript.
    Downloads: 0 This Week
    Last Update:
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  • 15
    just like mysql front, squid front is used to manage the squid tasks running on servers and monitor system status of each server, it also help you configure your ruels, users as well as other informations.
    Downloads: 0 This Week
    Last Update:
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