USB Host Diagnostics is a free Android application that allows you to determine your device's USB host capabilities. This feature can be found on recent Android-based smartphones and tablets, but it is often broken on both stock and custom firmware. This application was created to help you test your device's USB host capabilities for yourself, as it appears that Google and OEMs do not test USB host support when they push out new firmware and devices.

One of the main advantages of USB Host Diagnostics is that it can help you determine if your device supports USB host, even if OEMs advertise it but it is not supported at all. The app will also submit your results to the developer's website, creating a complete database of devices and firmware and their USB host support. This tool can also be useful for those porting firmware. The only requirements are Androidor newer, an optional root, a USB OTG cable (unless your device has a full-size USB port), and a USB memory stick or another USB device to test the connection with.