Web Serial Terminal

Talk to serial devices from your browser, in text or hex, with nothing to install.

Works in Google Chrome, Microsoft Edge or Opera on a desktop computer. It runs in your browser: what you send and receive stays on your computer.

How to use it

Talk to USB-to-serial adapters, Arduino, ESP32 and Pico boards, built-in COM ports and Bluetooth serial devices. There’s nothing to install.

1.
Add your port
Click Add port… and your browser lists the serial ports on your computer, such as COM3 on Windows or cu.usbserial-1410 on macOS. Pick one to let this page use it.
2.
Check the Ports list
Allowed ports appear under Ports and update on their own when a device is plugged in or removed. Refresh checks again, and Forget removes this page’s access to the selected port.
3.
Connect
Choose the baud rate, data bits, parity, stop bits and flow control, then click Connect or double-click the port. If your rate isn’t listed, pick Custom… and type it in.
4.
Read what comes in
Received data appears in the terminal. Switch between Text and Hex, and turn on Timestamps to see when each line arrived.
5.
Send data
Type in the box at the bottom and press Enter. Text mode adds the line ending you choose (LF, CR, CR+LF or none). Hex mode sends exactly the bytes you type, such as 48 65 6C 6C 6F 0D 0A; it also accepts 0x48,0x65 or 48656C. Use ↑ and ↓ to recall earlier messages.
6.
Set DTR and RTS
These boxes switch the control lines. Many dev boards reset when DTR changes.
7.
Save your log
Save log downloads the terminal’s contents as a text file. The terminal keeps the most recent 2 MB or so, and older output is dropped from the screen.

Google Chrome, Microsoft Edge or Opera on Windows, macOS, Linux or ChromeOS. Firefox and Safari don’t support Web Serial.
A driver for your adapter, if your computer doesn’t include one. Some CH340 and CP210x adapters need one on older Windows and macOS versions.

The port won’t open. A port can only be open in one program at a time. Close the Arduino IDE serial monitor, PuTTY, screen and other browser tabs, then connect again.
The port isn’t in the list. Browsers only show ports you’ve allowed, so click Add port… once. Chrome remembers your choice for next time.
The port has a different name. Browsers hide names like COM3 from web pages, so ports are labeled by USB vendor and product ID instead.