Gmail is a free, advertising-supported webmail, POP3 (Post Office Protocol), and IMAP (Internet Message Access Protocol) service provided by Google. Gmail was launched as an invitation-only beta release (Software release life cycle#Beta) on April 1, 2004 and it became available to the general public on February 7, 2007, though still with beta status. asof200912, it has 176 million users monthly. The service was upgraded from beta status on July 7, 2009, along with the rest of the Google Apps suite.

With an initial storage capacity offer of 1 GB (Gigabyte) per user, Gmail significantly increased the webmail standard for free storage from the 2 to 4 MB (Megabyte) its competitors offered at that time. Gmail has a search (search engine)-oriented interface and a "conversation view" similar to an Internet forum. Software developers know Gmail for its pioneering use of the Ajax programming (Ajax (programming)) technique. Gmail runs on Google GFE (Google Web Server)/2.0 on Linux.