Monitor Your Arduino or ESP32 in Real Time

A free browser serial monitor powered by the Web Serial API. Connect any Arduino, ESP32, or compatible device, watch incoming data in a live console, send commands, and plot numeric telemetry — all without installing software.

How to Use the Serial Monitor

Connect your device

Click Connect, select the correct baud rate, then choose your serial port from the browser picker. Advanced settings (data bits, parity, flow control) are available if needed.

Read incoming data

Incoming bytes are decoded as UTF-8 lines and shown in the console. Toggle timestamps or auto-scroll to suit your workflow.

Send commands

Type a command in the send box and press Enter or the Send button. Choose the line ending that matches your firmware (usually LF or CRLF).

Visualise telemetry

If your firmware outputs comma-separated numbers (e.g. "1.2,3.4") or label:value pairs (e.g. "temp:24.5 rpm:1200"), the plotter will graph them automatically.

Debug your microcontroller with a live browser-based serial console

Web Serial not supported

This tool requires the Web Serial API, which is supported in Chrome 89+, Edge 89+, and Opera 76+ on desktop over HTTPS.

Chrome 89+ Edge 89+ Opera 76+

Make sure you are on HTTPS and using a supported browser.

Features

Live TX/RX console with optional timestamps and smart auto-scroll Telemetry plotter parses comma-separated values and label:value pairs Configurable baud rate (300 – 2 000 000) plus data bits, stop bits, parity Send commands with selectable line endings (LF, CRLF, CR, none) Export the full session log as a .txt file Auto-handles device unplug — cleans up reader and port gracefully

FAQ

Which browsers support Web Serial?

Chrome 89+, Edge 89+, and Opera 76+ on desktop. Firefox and Safari do not support Web Serial. The page must be served over HTTPS.

Can I use this with Arduino?

Yes. Upload your sketch, close the Arduino IDE's serial monitor, then connect here with the same baud rate. The tool works with any device that exposes a USB-serial port.

How does the plotter work?

The plotter parses each incoming line. If the line contains only comma-separated numbers it plots them as channels ch1, ch2, etc. If it finds label:value pairs (e.g. "temp:25.3") it plots each label as a named series.

What line ending should I use?

Most Arduino sketches use Serial.println() which appends CRLF. Select "CRLF (\r\n)" for those. For raw commands with no newline, choose "No line ending".

What happens if the device is unplugged?

The read loop detects the error, shows a warning toast, logs the disconnection in the console, and resets the connection state cleanly.

💡 Want us to improve this tool just for you?

We can — and it's free! Just send us a quick message with your idea. If you'd like to discuss it in detail, leave your email and we'll get back to you. You can stay anonymous.

How do you rate this tool?

Thank you for your rating!

Change my rating

Want to leave a comment?

Want to share more? Leave a comment!

Thank you! Your comment will appear after moderation.

Who is this tool for?

Published 18 May 2026 Updated 21 May 2026