13 Amazing Open Source Email Clients for Desktop in 2026
Reviews, comparison, screenshots and more for the 13 amazing open-source email clients for Desktop.
Email Client Screenshots
Mozilla Thunderbird
Mozilla Thunderbird is an open-source email client for Desktop and is written in the JavaScript & C++ programming language. The official description from its website says, "Access all your messages, calendars, and contacts in one fast app."
Apple Mail
Apple Mail is a closed-source and proprietary email client for Desktop. The official description from its website says, "Mail is an email client included by Apple Inc. with its operating systems macOS, iOS, iPadOS and watchOS... With Mail on iCloud.com, you can send and receive email from your iCloud Mail account using a web browser."
Balsa
Balsa is an open-source email client for Desktop and is written in the C programming language. The official description from its website says, "Balsa is an e-mail client for GNOME, highly configurable and incorporating all the features you would expect in a robust mail client."
Claws Mail
Claws Mail is an open-source email client for Desktop and is written in the C (GTK) programming language. The official description from its website says, "Claws Mail is an email client (and news reader), based on GTK+..."
Cypht
Cypht is an open-source email client for Desktop and is written in the PHP programming language. The official description from its website says, "Lightweight Open Source webmail written in PHP and JavaScript."
GNOME Evolution
GNOME Evolution is an open-source email client for Desktop and is written in the C (GTK) programming language. The official description from its website says, "Evolution is a personal information management application that provides integrated mail, calendaring and address book functionality."
GNUMail
GNUMail is an open-source email client for Desktop and is written in the Objective-C programming language. The official description from its website says, "An email client for GNUstep."
Geary
Geary is an open-source email client for Desktop and is written in the Vala (GTK) programming language. The official description from its website says, "Geary is an email application built around conversations for the GNOME desktop."
KMail (Kontact)
KMail (Kontact) is an open-source email client for Desktop and is written in the C++ programming language. The official description from its website says, "KMail is the email component of Kontact, the integrated personal information manager from KDE."
RainLoop
RainLoop is an open-source email client for Desktop and is written in the PHP programming language. The official description from its website says, "Simple, modern & fast web-based email client."
Roundcube
Roundcube is an open-source email client for Desktop and is written in the PHP programming language. The official description from its website says, "Roundcube webmail is a browser-based multilingual IMAP client with an application-like user interface."
SnappyMail
SnappyMail is an open-source email client for Desktop and is written in the PHP programming language. The official description from its website says, "Simple, modern, lightweight & fast web-based email client."
Sylpheed
Sylpheed is an open-source email client for Desktop and is written in the C & GTK+ programming language. The official description from its website says, "Sylpheed is a simple, lightweight but featureful, and easy-to-use e-mail client."
Email Client Comparison
| Name | Description | Screenshot | Platforms | Language | Website | Wikipedia |
|---|---|---|---|---|---|---|
| Mozilla Thunderbird ⭐ Preferred | Access all your messages, calendars, and contacts in one fast app. | Screenshot |
| JavaScript & C++ | Website | Wikipedia |
| Apple Mail | Mail is an email client included by Apple Inc. with its operating systems macOS, iOS, iPadOS and watchOS... With Mail on iCloud.com, you can send and receive email from your iCloud Mail account using a web browser. | Screenshot |
| Proprietary | Website | Wikipedia |
| Balsa | Balsa is an e-mail client for GNOME, highly configurable and incorporating all the features you would expect in a robust mail client. | Screenshot |
| C | Website | Wikipedia |
| Claws Mail | Claws Mail is an email client (and news reader), based on GTK+... | Screenshot |
| C (GTK) | Website | Wikipedia |
| Cypht | Lightweight Open Source webmail written in PHP and JavaScript. | Screenshot |
| PHP | Website | |
| GNOME Evolution | Evolution is a personal information management application that provides integrated mail, calendaring and address book functionality. | Screenshot |
| C (GTK) | Website | Wikipedia |
| GNUMail | An email client for GNUstep. | Screenshot |
| Objective-C | Website | Wikipedia |
| Geary | Geary is an email application built around conversations for the GNOME desktop. | Screenshot |
| Vala (GTK) | Website | Wikipedia |
| KMail (Kontact) | KMail is the email component of Kontact, the integrated personal information manager from KDE. | Screenshot |
| C++ | Website | Wikipedia |
| RainLoop | Simple, modern & fast web-based email client. | Screenshot |
| PHP | Website | Wikipedia |
| Roundcube | Roundcube webmail is a browser-based multilingual IMAP client with an application-like user interface. | Screenshot |
| PHP | Website | Wikipedia |
| SnappyMail | Simple, modern, lightweight & fast web-based email client. | Screenshot |
| PHP | Website | |
| Sylpheed | Sylpheed is a simple, lightweight but featureful, and easy-to-use e-mail client. | Screenshot |
| C & GTK+ | Website | Wikipedia |