OLED Saver is a free Android app developed by ezjay:systems. It falls under the category of Utilities & Tools and is specifically designed to prevent screen burn-in on susceptible devices such as those with OLED and AMOLED displays. The app fills the screen with pure black and prevents the device from going to sleep while it is the foreground app.

This app is useful in a variety of situations. For example, during video chat or conferencing, it can keep the camera on and the call alive without burning the app's logo into the display. If the video app supports overlays, those can still be drawn on top of OLED Saver. It can also be used when running a process in the background, such as a cryptocurrency miner, where you want to keep the device fully awake without damaging the screen or wasting power. Additionally, it can be used to keep your screen off while still having your phone active and unlocked for easy access.

It's important to note that while OLED Saver is specifically designed for OLED and AMOLED displays, it also works on LCD screens. The screen will be as black as the screen can manage, but the backlight will usually remain on. If you find this app useful, leave a review and let the developers know how you use it!