Facebook is planning to bring a dark mode to its Android application, finally. This information comes from Jane Manchun Wong, who successfully shared Facebook-related info in the past, a number of times.
As most of you know by now, Facebook's Messenger app received dark mode quite some time ago. In fact, Facebook's Messenger application received pitch dark mode which is optimized for OLED displays. User reactions to it were rather positive back when it arrived.
The source did share one screenshot of the upcoming dark mode, though do note that this is still a work in progress. Once it becomes official, it may look different to what you can see here. In other words, Facebook may opt to introduce a pitch dark mode, like on its Messenger app. In other words, the background may not be dark gray, but completely black.
The source also says that it seems to be in the early stages of development. She also says that it may take some time for an app such as Facebook to be completely adapted to a dark theme. Don't expect this feature to come your way anytime soon.
Facebook will probably announce that the dark mode is coming way before it arrives, at least that's what the company did with Messenger's dark mode. It took the company months to deliver it after it was announced.
Facebook seems to be following a trend that started a while back. We've been seeing dark theme apps for a long time, but Google really got the ball rolling. The company started dark-theming its applications with Android 9 Pie, more or less. Android 9 Pie removed a ton of colors from the design of Google's apps, so the company wanted to counter that by offering users an alternative to all the white color that appears in apps now. On top of that, dark themes can save you some battery on smartphones with OLED displays. That's another reason why Google started doing it.
Many other companies did it based on Google's example, those that did not have a dark theme option already. Facebook is one of the most popular social media applications for Android, if not the most popular one, so many people will be happy to hear this news.
Google already released dark mode for a ton of its applications, including YouTube, Contacts, Phone, Messages, Google Keep (aka Keep Notes), and others. Even Google Chrome received the dark mode, though it needs to be activated through developer options. Dark mode for Chrome is still not perfect. The company will release a new update which will considerably improve dark mode in Chrome soon. That update recently rolled out to Chrome Beta, so it's coming to Chrome stable soon.
Google still has to convert several of its apps, including Gmail and Play Store. Some code leaked not long ago, confirming that a dark theme is coming to Gmail. Same will almost certainly happen with the Play Store as well, but nothing has been confirmed just yet.