Serial Monitor

Connect to an Arduino, ESP32, or any USB serial device directly in your browser. Send commands, view live output in the terminal, and plot numeric sensor values on the real-time chart.

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How It Works

This tool uses the Web Serial API, a browser capability (Chrome/Edge 89+) that lets web pages communicate with serial devices over USB without any drivers or installed software. When you click Connect, the browser shows a native port picker where you select your Arduino, ESP32, or other device.

Connection: You select the baud rate and serial configuration to match your device firmware (e.g. 9600 or 115200 for most Arduinos). The browser opens the port and streams bytes in and out through a ReadableStream / WritableStream interface.

Terminal: Incoming bytes are decoded as UTF-8 text and displayed line by line. Hex view shows raw byte values. The log can be saved as a .txt file for later analysis.

Plotter: Each received line is parsed for numeric values. Lines like temperature:25.3 or 25.3 45.1 1024 are recognized automatically. Named fields (key:value) become labeled channels; unnamed columns get channel numbers. A sliding window of the last 200 samples is drawn on the canvas chart.

Sending: Text typed in the Send field is encoded as UTF-8 and written to the device with your chosen line-ending (most Arduino Serial.readStringUntil('\n') sketches expect Newline).

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Tips

• Make sure your sketch calls Serial.begin(115200) and choose 115200 in the baud selector.
• Only one app can hold the serial port at a time. Close the Arduino IDE Serial Monitor before connecting here.
• For the plotter, send values like sensor1:12.3,sensor2:45.6 or space-separated numbers for automatic channel detection.
• Enable Timestamps to see exactly when each line arrived, useful for timing analysis.
• The Web Serial API requires a secure context (HTTPS or localhost). It does not work over plain HTTP on a remote host.

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