Gmail is a free email service provided by Google. As of 2019, it had 1.5 billion active users worldwide making it the largest email service in the world. A user typically accesses Gmail in a web browser or through the official mobile application. Google also supports the use of email clients via the POP and IMAP protocols. At its launch in 2004, Gmail provided a storage capacity of one gigabyte per user, which was significantly higher than its competitors offered at the time. Today, the service comes with 15 gigabytes of storage for free, which is divided among other Google services, such as Google Drive, and Google Photos. Users in need of more storage can purchase Google One to increase this 15GB limit. Users can receive emails up to 50 megabytes in size, including attachments, while they can send emails up to 25 megabytes. In order to send larger files, users can insert files from Google Drive into the message. Gmail has a search-oriented interface and a 'conversation view' similar to an Internet forum. The service is notable among website developers for its early adoption of Ajax. (Source: Wikipedia.org, CC BY-SA)