Gmail's user interface designer, Kevin Fox, intended users to feel as if they were always on one page and just changing things on that page, rather than having to navigate to other places.
Gmail's interface also makes use of 'labels' (tags) – that replace the conventional folders and provide a more flexible method of organizing email; filters for automatically organizing, deleting or forwarding incoming emails to other addresses; and importance markers for automatically marking messages as 'important'.
The service is notable among website developers for its early adoption of Ajax.
Google's mail servers automatically scan emails for multiple purposes, including to filter spam and malware, and to add context-sensitive advertisements next to emails.
and was the first app on the Google Play Store to hit one billion installations on Android devices.
According to a 2014 estimate, 60% of mid-sized US companies, and 92% of startups, were using Gmail.
Users can receive emails up to 50 megabytes in size, including attachments, while they can send emails up to 25 megabytes.
On April 1, 2005, the first anniversary of Gmail, the limit was doubled to two gigabytes of storage.
Georges Harik, the product management director for Gmail, stated that Google would "keep giving people more space forever." Users can buy additional storage, shared among Gmail, Google Drive and Google Photos, through a monthly subscription plan.
Other updates include a Confidential mode, which allows the sender to set an expiration date for a sensitive message or to revoke it entirely, integrated rights management and two-factor authentication.
In the April 2018 update the spam filtering banners got a redesign, with bigger and bolder lettering.