Claws Mail Alternatives and Similar Software

Thunderbird

Thunderbird is a free, open source, cross-platform e-mail, news and instant messaging client. The project strategy is modeled after Mozilla Firefox. It supports POP (storing mail locally on your hard drive so that it can be accessed without an internet connection), and IMAP. It features excellent mail filter capabilities and management. Thunderbird has strong support for using multiple accounts and identities, including automated signature features.

Free Open Source Mac Windows Linux BSD PortableApps.com ... Haiku

Feedly

Feedly is a better way to organize, read and share the content of your favorite sites. It weaves the content from the RSS feeds of your favorite websites into a fun magazine-like experience and provides seamless integration with social networks. Better Personalization - Organize your favorite blogs, news sites and Youtube channels and access them all in one place (or sync with Twitter and Facebook).

Freemium $ $ $ Web Android iPhone Chrome OS Android Tablet ... iPad Apple Watch Chrome Safari Kindle Fire Firefox

K-9 Mail

K-9 is an open source email client for Android with multi-folder sync, email signatures, Bcc-to-self, return-address configuration, keyboard shortcuts, Exchange Support, message flagging, IMAP deletes, saving attachments, configurable notifications and more.

• Best open-source mail client for android! Guest • Nov 2018 Disagree   Agree

Free Open Source Android Android Tablet

Microsoft Office Outlook

Microsoft Outlook, part of the Microsoft Office Suite (not to be confused with Microsoft Outlook Express), is a personal information manager that lets you manage your e-mail, calendar, contacts, and tasks. Outlook is included in Office Home (one-time purchase), Office 365 (monthly or yearly subscription) or available as free app for Android, iOS and Windows Phone.

Freemium $ $ $ Mac Windows Web Android iPhone ... Android Tablet Windows Phone iPad Apple Watch Android Wear

QuiteRSS

Features: Feed and news filters: new, unread, starred, deleted (for news until restart application) User filters Proxy configuration: automatic or manual Feed import wizard: Search feed URL if site URL was entered Embedded browser (Webkit core) Mark news starred Automatic update feeds: on startup, by timer Automatic cleanup on close using criteria Enable/Disable images in news preview Ability to quickly hide feed tree (for comfortable viewing)...

Free Open Source Mac Windows Linux BSD PortableApps.com

eM Client

eM Client is a full featured email client with a modern and easy to use interface. - offers calendar, tasks, contacts and even chat. - supports all major services including Gmail, Exchange, iCloud, and Outlook.com. - easily imports your data from most of the other e-mail clients. This includes Microsoft Outlook, Outlook Express, Windows Mail, Windows Live Mail, Thunderbird, The Bat and more. - fully supports touch devices like touch-enabled laptops, tablets and hybrid devices.

Freemium Windows

Evolution

Evolution is the official personal information manager and workgroup information management tool for GNOME. It combines e-mail, calendar, address book, and task list management functions. Features E-mail retrieval with the POP and IMAP protocols and e-mail transmission with SMTP. Secure network connections encrypted with SSL, TLS and STARTTLS. E-mail encryption with GnuPG and S/MIME. E-mail filters.

Free Open Source Linux BSD S/MIME GNOME OpenPGP

Reeder

Reeder is an RSS reader and client for multiple services like: Feedly , Feedbin , FeedHQ , Inoreader , NewsBlur , The Old Reader , BazQux Reader , Instapaper . Don't want to use a third-party service? Reeder also supports local/standalone RSS (no sync).

Commercial Mac iPhone iPad

Apple Mail

Apple Mail changes the way you interact with your email every day. Mail displays your messages and open email side by side in a widescreen, two-column view. The favorites bar below the toolbar works much like a bookmarks bar in a web browser, giving you one-click access to your mail folders. A compact preview of each message — including the first two lines — lets you scan your messages at a glance.

Free Mac iPhone iPad

Mailbird

Mailbird is a Windows based email client which design and style match Windows 7, 8 and XP’s native styles. Mailbird provides clean, simple and lightning fast email experience. The current free version of Mailbird has Multi Account support for Gmail, Yahoo, Outlook.com, iCloud, and any other IMAP/POP3 email provider. S/MIME and PGP are not supported.

Freemium $ $ $ Windows

Spark

Smart Inbox automatically detects if an email is personal, a notification or a newsletter and groups it with similar emails for easy batch processing using beloved swipes. With just a glance, you can see if emails are important or just a product announcement from a service you've never used. We all love the feeling of accomplishment when we have finally dealt with our inbox. Spark makes this easy to achieve. Quickly process your emails, swiping to archive or delete as necessary.

Free Mac iPhone iPad Apple Watch

Postbox

Postbox is an email application that helps you organize your work life and get stuff done. It has all the elegance and simplicity of Apple Mail, but with more power and flexibility to manage even the most demanding workloads. Key Features * Ultra-Fast Search - Instantly find messages, attachments, images, links, and contacts. * Conversation Views - Make sense of email threads through chronological message views.

Commercial Mac Windows

Geary

Geary is a lightweight email program designed around conversations and built for the GNOME desktop. It's designed to let you read your email quickly and effortlessly. Its interface is based on conversations, so you can easily read an entire discussion without having to click from message to message. Geary is written in Vala .

Free Open Source Linux BSD GNOME

Opera Mail

Opera Mail powerfully organizes, indexes, and sorts your messages. It has spam filtering (both automated and Bayesian), supports POP3 and IMAP, newsgroups as well as Atom and RSS feeds. Opera Mail uses one database that keeps an index of all mail, and sorts the messages automatically into several "views" or accesspoints. Messages are automatically sorted by type, such as mailing lists, and mail with attachments . This approach to indexing allows for quicker access to messages.

• Discontinued Opera Mail is no longer updated and supported, but last version, 1.0.1044, released in February 2016, can be still downloaded from the official website.

Free Mac Windows PortableApps.com

Mutt

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 list-reply, active development community, POP3 support, IMAP support.

Free Open Source Mac Windows Linux Xfce

Open365

Open365 is an Open Source, self-hosted file sync and cloud apps platform including a full LibreOffice Online. You can also access your email, calendar and contacts using KDE Kontact. Everything is accessible from a simple webpage using any HTML5 browser.

• Discontinued The project seems to be no longer developed. Last commit on the GitHub repo was made on June 27th, 2016, but it can be still downloaded and installed.

Free Open Source Android Self-Hosted

Sylpheed

Sylpheed is a simple, lightweight but featureful, and easy-to-use e-mail client (mailer, MUA). Sylpheed runs on many systems such as Windows, Linux, BSD, Mac OS X and other Unix-like systems. Sylpheed uses GTK+ GUI toolkit. The newest version of Sylpheed works with GTK+ 2.4 or later (2.6 or later is recommended). Sylpheed is a free software distributed under the GNU GPL (the library part is GNU LGPL). You can freely use, modify and redistribute it under the license.

Free Open Source Mac Windows Linux BSD PortableApps.com

Microsoft Mail and Calendar

Windows 10 has Mail and Calendar apps already built in. With the Mail application you can now easily see all message from your favorite people, more clearly organize social updates and newsletters, and use the popular “Sweep” feature to clean up your inbox.

Free Windows Windows S

The Bat

The Bat! is a secure email client software, built to protect your correspondence against third-parties. The Bat! protects your information through multiple encryption streams with the options to encrypt your emails on disk and during communication through an SSL/TLS connection. Free of global email providers that keep your messages in the cloud, and free of Web clients, The Bat! ensures your data stays private.

Commercial Windows S/MIME OpenPGP

Kontact - KMail

KMail is the email component of Kontact, the integrated personal information manager of KDE. Kontact is a personal information manager and groupware software suite for KDE. It supports calendars, contacts, notes, to-do lists, news, and email. It uses KParts to embed the various applications (KMail, KAddressBook, Akregator, etc.) into the container application.

Free Open Source Mac Windows Linux BSD

TypeApp

TypeApp is an all-free, beautifully designed, universal email app, capable of managing unlimited number of mail accounts from various providers, allowing for smart push notifications while enabling personalization across multiple email accounts. TypeApp is the perfect replacement for your email app. With a powerful unified accounts experience packaged in an intuitive and easy to use design, TypeApp provides a top notch email service.

Free Personal Android iPhone Android Tablet iPad Android Wear ... Kindle Fire

Spike

Spike is the world’s first conversational email app. We’re upgrading the way you work, saving you and your team time, sanity, and a lot of headaches. At Spike, our goal is simple: to bring all of your communication -- your emails, chats, calls, team collaborations, tasks, voice notes, everything -- to one place. It’s what your team has been looking for in a productivity and messaging app, but easier, and all from your inbox.

Freemium $ $ $ Mac Windows Android iPhone Android Tablet ... iPad

Trojitá

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.

Free Open Source Windows Linux

Cronycle

Once it was easy find content relevant to your business; you’d go to the national newspapers and perhaps the trade press. Maybe there was a conference a year where you’d discover a business book. Making decisions with this information was also easy. Everyone worked in the same office so everyone could discuss articles and use their experience to create actionable business intelligence.

Freemium Web iPhone

FairEmail

This email app might be for you if your current email app: takes long to receive or show messages can manage only one mailbox cannot show conversations cannot work offline looks outdated is not maintained stores your email on their servers is closed source, potentially violating your privacy

Free Open Source Android Android Tablet F-Droid