A lightweight and user-friendly Modbus RTU sniffer tool with a graphical interface.
Easily analyze and debug communication between PLCs, HMIs, and other Modbus RTU devices via serial ports.

• 🧰 Sniffs raw Modbus RTU frames from serial ports (RS-485, USB)
• 🖥️ GUI interface built with PyQt6
• 📋 Frame table: Real-time decoded Modbus traffic
• 🌈 Color-coded logging of request–response frames
• 🪟 Cross-platform: Windows & Linux
• 🆓 MIT licensed, open-source

Install directly from PyPI:

pip install modbus-sniffer

or download Binary files for Ubuntu and Windows from here.

You can also build and install app from sourcess. Click here for deatails about it.

modbus-sniffer-gui

To list all options:

modbus-sniffer -h

Example of runnig sniffer on ttyUSB0 with baud 115200 and no parity:

modbus-sniffer -p /dev/ttyUSB0 -b 115200 -r none

For more usage options, development guide, and installation from source, visit the GitHub repository:

👉 ModbusSniffer on GitHub

Please see docs/CONTRIBUTING.md for development setup and contribution guidelines.

MIT License — see the LICENSE file for details.
This project is a fork of BADAndrea ModbusSniffer, maintained by niwciu with enhancements described above.

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