Instant messaging (IM) technology is a type of online chat allowing immediate transmission of messages over the Internet or another computer network. Messages are typically transmitted between two or more parties, when each user inputs text and triggers a transmission to the recipient(s), who are all connected on a common network. It differs from email in that conversations over instant messaging happen in real-time. Most modern IM applications use push technology and also add other features such as emojis, file transfer, chatbots, voice over IP, or video chat capabilities.
Webmail is an email service that can be accessed using a standard web browser. It contrasts with email service accessible through a specialised email client software. Additionally, many internet service providers (ISP) provide webmail as part of their internet service package. Similarly, some web hosting providers also provide webmail as a part of their hosting package.
Microsoft Outlook is a personal information manager software system from Microsoft, available as a part of the Microsoft 365 software suites. Though primarily being popular as an email client for businesses, Outlook also includes functions such as calendaring, task managing, contact managing, note-taking, journal logging, web browsing, and RSS news aggregation.
Hushmail is an encrypted proprietary web-based email service offering PGP-encrypted e-mail and vanity domain service. Hushmail uses OpenPGP standards. If public encryption keys are available to both recipient and sender, Hushmail can convey authenticated, encrypted messages in both directions. For recipients for whom no public key is available, Hushmail will allow a message to be encrypted by a password and stored for pickup by the recipient, or the message can be sent in cleartext. In July, 2016, the company launched an iOS app that offers end-to-end encryption and full integration with the webmail settings. The company is located in Vancouver, British Columbia, Canada.
Microsoft Exchange Server is a mail server and calendaring server developed by Microsoft. It runs exclusively on Windows Server operating systems.
Yahoo! Mail is an email service offered by the American company Yahoo, Inc. The service is free for personal use, with an optional monthly fee for additional features. Business email was previously available with the Yahoo! Small Business brand, before it transitioned to Verizon Small Business Essentials in early 2022. Launched on October 8, 1997, as of January 2020, Yahoo! Mail has 225 million users.
ESET NOD32 Antivirus, commonly known as NOD32, is an antivirus software package made by the Slovak company ESET. ESET NOD32 Antivirus is sold in two editions, Home Edition and Business Edition. The Business Edition packages add ESET Remote Administrator allowing for server deployment and management, mirroring of threat signature database updates and the ability to install on Microsoft Windows Server operating systems.
SquirrelMail is a project that aims to provide both a web-based email client and a proxy server for the IMAP protocol.
The following tables compare general and technical features of notable email client programs.
The Internet Messaging Program or IMP is a webmail client. It can be used to access e-mail stored on an IMAP server. IMP is written in PHP and a component of the collaborative software suite Horde.
Roundcube is a web-based IMAP email client. Roundcube's most prominent feature is the pervasive use of Ajax technology. Roundcube is free and open-source software subject to the terms of the GNU General Public License (GPL-3.0-or-later), with exceptions for skins and plugins.
The following tables compare general and technical information for a number of notable webmail providers who offer a web interface in English.
GMX Mail is a free advertising-supported email service provided by GMX. Users may access received GMX Mail via webmail, or using POP3 or IMAP4 protocols. Mail is sent using SMTP. Founded in 1997, GMX is a subsidiary of Ionos AG, a stock-listed company in Germany, and a sister company to Ionos and Fasthosts Internet. In addition to an email address, each GMX account includes a Mail Collector, Address Book, Organizer, and File Storage. Every user can register up to 10 individual GMX email addresses. Popup ads are displayed to all users, including premium, at GMX login; as of 2021 GMX was the only large email provider using popup ads.
Outlook.com, formerly Hotmail, is a free personal email service offered by Microsoft. This includes a webmail interface featuring mail, calendaring, contacts, and tasks services. Outlook can also be accessed via email clients using the IMAP or POP protocols.
CommuniGate Pro (CGatePro) is a highly scalable carrier grade unified communications server, as well as a development platform. The system is Internet Protocol based. The server is a single process, multi-threaded application written entirely in C++. APIs are available for authentication, helper applications and directory services.
GroupWise is a messaging and collaboration platform from OpenText that supports email, calendaring, personal information management, instant messaging, and document management. The GroupWise platform consists of desktop client software, which is available for Windows,, and the server software, which is supported on Windows Server and Linux.
Proton Mail is a Swiss end-to-end encrypted email service founded in 2013 headquartered in Plan-les-Ouates, Switzerland. It uses client-side encryption to protect email content and user data before they are sent to Proton Mail servers, unlike other common email providers such as Gmail and Outlook.com. The service can be accessed through a webmail client, the Tor network, or dedicated iOS and Android apps.
The first release of Microsoft Exchange Server was version 4.0 in April 1996, when it was sold as an upgrade to Microsoft Mail 3.5. Before that, Microsoft Mail v2.0 was replaced in 1991 by "Microsoft Mail for PC Networks v2.1", based on Network Courier from its acquisition of Consumers Software. Exchange Server was an entirely new X.400-based client–server mail system with a single database store that also supported X.500 directory services. During its development, Microsoft migrated their own internal email from a Xenix-based system to Exchange Server from April 1993, with all 32,000 Microsoft mailboxes on Exchange by late 1996. The directory used by Exchange Server eventually became Microsoft's Active Directory service, an LDAP-compliant directory service. Active Directory was integrated into Windows 2000 as the foundation of Windows domains.
MDaemon Email Server is an email server application with groupware functions for Microsoft Windows, first released by Alt-N Technologies in 1996.
The JSON Meta Application Protocol (JMAP) is a set of related open Internet Standard protocols for handling email. JMAP is implemented using JSON APIs over HTTP and has been developed as an alternative to IMAP/SMTP and proprietary email APIs such as Gmail and Outlook. Additional protocols and data models being built on top of the core of JMAP for handling contacts and calendar synchronization are meant to be potential replacements for CardDAV and CalDAV, and other support is currently in the works.
