- Connect the Arduino to this computer with a USB data cable.
- Close the Arduino IDE Serial Monitor or any other program already using the port.
- Set the baud rate to match
Serial.begin(...) in the sketch.
- Select Connect device, then choose the board in the browser prompt.
- Use the command console to send text back to the sketch.
Browser requirement: Web Serial needs a compatible Chromium-based desktop browser and a secure page. Host this file over HTTPS. Browsers may also treat local development origins such as localhost as secure.
The page never uploads serial data. Communication is directly between this browser and the selected local device.