"Four years after launching Inbox in 2014, we've learned a lot about how to make email better-and we've taken popular Inbox experiences and added them into Gmail to help more than a billion people get more done with their emails everyday," Google product manager Matthew Izatt said in a blog post.
"As we look to the future, we want to take a more focused approach that will help us bring the best email experience to everyone. As a result, we're planning to focus solely on Gmail and say goodbye to Inbox by Gmail at the end of March 2019."
Inbox is available as a mobile app and as a web interface alternative to viewing Gmail accounts.
Across the lifetime of Inbox, some of its features -- such as smart compose, nudges, and email snoozing -- have found their way back into Gmail.