Electronic mail is a method of transmitting and receiving messages using electronic devices. It was conceived in the late–20th century as the digital version of, or counterpart to, mail. Email is a ubiquitous and very widely used communication medium; in current use, an email address is often treated as a basic and necessary part of many processes in business, commerce, government, education, entertainment, and other spheres of daily life in most countries.
In computing, the Internet Message Access Protocol (IMAP) is an Internet standard protocol used by email clients to retrieve email messages from a mail server over a TCP/IP connection. IMAP is defined by RFC 9051.
Within the Internet email system, a message transfer agent (MTA), mail transfer agent, or mail relay is software that transfers electronic mail messages from one computer to another using the Simple Mail Transfer Protocol. In some contexts, the alternative names mail server, mail exchanger, or MX host are used to describe an MTA.
In computing, the Post Office Protocol (POP) is an application-layer Internet standard protocol used by e-mail clients to retrieve e-mail from a mail server. Today, POP version 3 (POP3) is the most commonly used version. Together with IMAP, it is one of the most common protocols for email retrieval.
The Simple Mail Transfer Protocol (SMTP) is an Internet standard communication protocol for electronic mail transmission. Mail servers and other message transfer agents use SMTP to send and receive mail messages. User-level email clients typically use SMTP only for sending messages to a mail server for relaying, and typically submit outgoing email to the mail server on port 587 or 465 per RFC 8314. For retrieving messages, IMAP is standard, but proprietary servers also often implement proprietary protocols, e.g., Exchange ActiveSync.
An email client, email reader or, more formally, message user agent (MUA) or mail user agent is a computer program used to access and manage a user's email.
Eudora is an email client that was used on the classic Mac OS, Mac OS X, and Microsoft Windows operating systems. It also supported several palmtop computing platforms, including Newton and the Palm OS. Eudora was succeeded by Eudora OSE. In 2018, after being years out of print, the software was open-sourced by the Computer History Museum.
AOL Mail is a free web-based email service provided by AOL, a division of Yahoo! Inc.
Push email is an email system that provides an always-on capability, in which when new email arrives at the mail delivery agent (MDA), it is immediately, actively transferred (pushed) by the MDA to the mail user agent (MUA), also called the email client, so that the end-user can see incoming email immediately. This is in contrast with systems that check for new incoming mail every so often, on a schedule. Email clients include smartphones and, less strictly, IMAP personal computer mail applications.
The following tables compare general and technical information for a number of notable webmail providers who offer a web interface in English.
The Courier Mail Server is a mail transfer agent (MTA) server that provides SMTP, IMAP, POP3, SMAP, webmail, and mailing list services with individual components. It is best known for its IMAP server component.
hMailServer was a free email server for Windows created by Martin Knafve. It ran as a Windows service and includes administration tools for management and backup. It had support for IMAP, POP3, and SMTP email protocols. It could use external database engines such as MySQL, MS SQL or PostgreSQL, or an internal MS SQL Compact Edition engine to store configuration and index data. The actual email messages were stored on disk in a raw MIME format. As of January 15th, 2022, active support and development were officially halted, although version 5.6 will continue to receive updates for critical bugs.
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.
Invisible mail, also referred to as iMail, i-mail or Bote mail, is a method of exchanging digital messages from an author to one or more recipients in a secure and untraceable way. It is an open protocol and its java implementation (I2P-Bote) is free and open-source software, licensed under the GPLv3.
EmailTray is a lightweight email client for the Microsoft Windows operating system. EmailTray was developed by Internet Promotion Agency S.A., a software development d.
A mailbox provider, mail service provider or, somewhat improperly, email service provider is a provider of email hosting. It implements email servers to send, receive, accept, and store email for other organizations or end users, on their behalf.
Tor Mail was a Tor hidden service that went offline in August 2013 after an FBI raid on Freedom Hosting. The service allowed users to send and receive email anonymously to email addresses inside and outside the Tor network.
Mailbird is a desktop email client for Microsoft Windows, compatible with Windows 7 and all later versions. As well as sending and receiving emails, Mailbird includes managing calendar events and contacts from different email providers, social media, task management, file share, and video-conferencing integrations. Mailbird is offered via paid subscription, but also includes a free version.
SIGAINT was a Tor hidden service offering secure email services. According to its FAQ page, its web interface used SquirrelMail which does not rely on JavaScript. Passwords couldn't be recovered. Users received two addresses per inbox: one at sigaint.org for receiving clearnet emails and the other at its .onion address only for receiving emails sent from other Tor-enabled email services. Free accounts had 50 MB of storage space and expired after one year of inactivity. Upgraded accounts had access to POP3, IMAP, SMTP, larger size limits, full disk encryption, and never expired.
Mailfence is a secure and encrypted email service that offers OpenPGP based end-to-end encryption and digital signatures. It was launched in November 2013 by ContactOffice Group, which has been operating an online collaboration suite for universities and other organizations since 1999.
