Microsoft Exchange Server is the server side of a client–server, collaborative application product developed by Microsoft. It is part of the Microsoft Servers line of server products and is used by enterprises using Microsoft infrastructure products. Exchange’s major features consist of electronic mail, calendaring, contacts and tasks; support for mobile and web-based access to information; and support for data storage.

Exchange is a popular Microsoft messaging system that includes a mail server, an e-mail program (e-mail client), and groupware applications. Designed for use in a business setting, the Exchange server is often used in conjunction with Microsoft Outlook to take advantage of Outlook’s collaborative features, such as the ability to share calendars and contact lists.