Google had confirmed that it would be shutting down the Inbox by Gmail app at the end of March 2019 and the company is now showing alerts to its users that says the app will be going away in 15 days, i.e 2nd April. The company has gone and already shut down its messaging app Allo this month and will be shutting down goo.gl URL Shortener later this month along with Google+ on 2nd April as a part of the Spring Cleaning.
Inbox by Gmail app was Google's great platform to experiment with new ideas that include AI-powered experiences like Smart Reply, snoozing emails to later, nudges, high-priority notifications and more.
Bring there for almost four years, Google has migrated most of its features to Gmail as the revamped Gmail that was introduced this year comes with the same Inbox feature and to focus solely on Gmail, the company has decided to call it off for Inbox by Gmail.
Google is encouraging its users to use the new Gmail instead of Inbox and has asked users to manually disable Inbox access before March 2019 end.