Top Alternatives to Spark

Thunderbird is a open source mail client developed and maintained by Mozilla foundation.

Microsoft Outlook is a personal information manager from Microsoft.

Mailbird is a desktop email client for Windows 7, 8 and 10.

Apple Mail is an email client included with the operating systems macOS, iOS and watchOS by Apple Inc.

eM Client is a Windows based e-mail client for sending and receiving e-mails, managing calendars, contacts, and tasks.

K-9 Mail is an open source email client with support for multiple accounts, search, IMAP push email, multi-folder sync, flagging, filing, signatures.

Postbox is powerful, intuitive, ultra-customizable, speedy task manager.

Claws Mail is a free and open-source, GTK+-based email and news client. It offers easy configuration and an abundance of features.

The Bat! is an email program for Windows that protects the correspondence and empowers the users to handle large amounts of emails quickly and efficiently.

Airmail is a fast mail client for Mac and iPhone.

OpenProject is a web-based project management system for location-independent team collaboration.

Polymail is an email application for OS X and iOS known for its clean interface and additional features atop the Gmail platform.

Microsoft Mail and Calendar apps help you stay up to date on your email, manage your schedule and stay in touch with people you care about the most.

MailMate is an IMAP email client for macOS featuring extensive keyboard control, Markdown integrated email composition, advanced search conditions.

TypeApp is a mobile email client app.