Google said it was sending out invitations to selected Gmail users to try out the new service. Users can also email the company at inbox@google.com to get an invitation.
               
For now the new service is being provided alongside Gmail, which was launched in 2004. It will be available on the Web as well as on Android smartphones and iPhones.
               
"Inbox is by the same people who brought you Gmail, but it's not Gmail: it's a completely different type of inbox, designed to focus on what really matters," the company said in a blog post.
               
Google said Inbox displays real-time updates to emails – for example, showing the delivery status of items bought online.
               
It also shows reminders in a more accessible way that allows users to more easily keep track of chores and appointments.
               
The company said the new application also enhances features that are already available in Gmail that allow users to view purchases and bank account statements grouped together.
               
Google's shares were up 1.7 percent at USD 547.33 in early afternoon trading Nasdaq.