Difference between WebUSB and WebSerial

Question

I am working on a project that involve accessing USB port using browser. I have seen WebUSB API and WebSerial API. Though I can't seem to get what is the difference between them? Can someone highlight the difference?

Answer 1

The difference between the two APIs is how they interface with the operating system to communicate with the device. WebUSB uses the platform-specific USB API while Web Serial uses the platform-specific serial API. This matters because USB is lower level than serial and because not every serial device is a USB device. With WebUSB you will be able to communicate with many different classes of USB device, including serial devices, but it requires the operating system allow the browser to "claim" the USB interface, which means there can't already be a USB device driver present. With Web Serial you will be able to communicate with USB serial devices, but also other types of serial devices such as Bluetooth as well as built-in RS-232 ports and other UARTs. The tradeoff you make with using Web Serial to connect to a USB device is that the operating system needs to have the correct USB serial driver installed so that the device is available through the platform-specific serial API used by the browser to implement Web Serial.