Serial

Serial Port Debugger

Connect to local USB serial development boards, including COM port selection, permission guidance, baud settings, text/HEX send and receive, scheduled sending, and logs.

Connection and Permission

Idle

Flow

Open this HTTPS page with Chrome or Edge.
Plug the board into USB, confirm the driver is installed and no other serial tool is using it.
Click Select COM Port and authorize the device in the browser prompt.
Set baud rate and other parameters, then click Open Port.

Baud Rate Data Bits Stop Bits Parity Flow Control

No port selected.

Send

Send Format Text HEX

Append CRLF for text Scheduled Intervalms

Payload

Receive Log

Show HEX Auto scroll

Permissions and Troubleshooting

Browser Requirements

Serial connections from web pages mainly work in desktop Chrome, Edge, and similar browsers. Firefox, Safari, and iOS browsers generally cannot use it. The page must be HTTPS or localhost.

Permission

The browser only opens the port picker after a user click. Previously authorized devices can be selected again. To revoke permission, remove serial permission from the site settings near the address bar.

Open Failed

If opening fails, common causes are missing drivers, the device being used by Arduino IDE or another serial tool, mismatched baud settings, or a charge-only USB cable.

Privacy

Serial data is handled only in the current browser page and is not uploaded to the server. The browser requires explicit device selection and permission.