Apps similar to KMail include Thunderbird, which is free and open source. Other options are Betterbird, Evolution, Microsoft Outlook and Mailspring. There's no shortage of Email Clients like KMail, with more than 50 alternatives for Windows, Linux, Mac, Android and iPhone.
Mailpile is a modern, fast web-mail client with user-friendly encryption and privacy features. The development of Mailpile is funded by a large community of backers and all code related to the project is and will be released under an OSI approved Free Software license.
The powerful, full-featured Personal Information Manager for Windows offering Email, Synchronization, Portability, Network support, Android and iOS versions.
Estonia
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Secure email app for Mac, iPhone, Android and Windows with AI Copilot, PGP encryption, read receipts and one unified inbox.
Singapore
Mutt is a small but very powerful text-based mail client for Unix operating systems. Some of its features are: color support, message threading, MIME support (including RFC2047 support for encoded headers), PGP/MIME (RFC2015), various features to support mailing lists, including...
United States
Sylpheed is a simple, lightweight but featureful, and easy-to-use e-mail client (mailer, MUA).
Japan
The free Zimbra Desktop client allows you to meld the online and offline worlds – storing and synching your email, calendar, contacts, files and documents in the cloud, yet having them locally accessible when on the road.
United States
Japan
Engineered for iOS, macOS, and watchOS, this fast mail client supports multiple account types, custom actions, Smart Inbox filtering, unified inbox, privacy mode, email scheduling, snooze, third-party app integration, flexible personalization, and advanced workflow tools.
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No-frills, easy to use, easy to maintain Email client for Android based on the JSON Meta Application Protocol (JMAP).
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Mac IMAP email client featuring keyboard control, Markdown email composition, advanced search capabilities, smart mailboxes, automatic signature handling, cryptographic options with OpenPGP/S-MIME, tagging, multiple notifications, and customizable layouts including widescreen.
Trojitá, is a fast Qt IMAP e-mail client that respects open standards and facilitates modern technologies. Trojitá values vendor-neutrality that IMAP provides and is committed to be as interoperable as possible.
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