Facebook's star standalone app, Messenger, crossed 800 million monthly users at the close of 2015, the social network reported in a blog post on Thursday.
This reflects a significant increase, up from 500 million in late 2014—though a chunk of Messenger's growth can be attributed to Facebook's decision to nix in-app messaging from its flagship app, effectively forcing users to download Messenger.
As noted in Fast Company's December 2015 cover story, Facebook boasts 1.55 billion monthly users, which makes Messenger's numbers doubly impressive.
The app has eclipsed Facebook-wide growth over the past year, given that Facebook only gained about 200 million new monthly users since November 2014.
These metrics also highlight, by contrast, the glacial pace of Twitter's recent user growth: The company's total monthly user count is currently stagnating at about 320 million.
In 2015, Facebook spruced up Messenger with a slew of new features, including peer-to-peer payments and a snazzy digital assistant called M. The company is also testing e-commerce capabilities that will give retailers the ability to sell directly to consumers on the platform.
Facebook also recently released a software development kit that empowers developers to create chat bots for Messenger, which in turn will give users in-app access to third-party services. One such chat bot integration was already revealed back in December, when Facebook made it possible for users to order Uber rides from within Messenger.