Speed Overlay is an Android app developed by zuim.de Apps that allows you to display your speed on top of other applications like navigation apps. This feature is especially useful in apps that don't offer a native speed display. With Speed Overlay, you can customize the layout and sizing of the display, toggle it on and off with a notification or shortcut, and choose between m/s, km/h, mph, or knots for your unit of measurement.

One of the standout features of Speed Overlay is its ability to display GPS accuracy, height, and coordinates. You can even hide the unit name and invert the colors of the overlay. The app is completely free and ad-free, with no limitations on its use. You can also use it with automation tools like Tasker or Automate, and there are shortcuts available to easily start, stop, or toggle the overlay.