Best Self Hosted Alternatives to Mach3

CNCjs is a web-based user interface and server for controlling CNC machines by streaming G-code to common firmware such as Grbl, Marlin, Smoothieware, and TinyG/g2core. It runs on a computer like a Raspberry Pi or laptop and connects to the controller over a serial link (USB, Bluetooth serial, or serial-to-WiFi).

Key Features

• Supports multiple CNC firmware targets including Grbl/Grbl-Mega, Marlin, Smoothieware, TinyG, and g2core
• G-code sender with real-time status, console, and 6-axis digital readout (DRO)
• Toolpath visualization with 3D preview
• Multi-client access to the same machine session (multiple HTTP connections)
• Responsive interface suitable for tablets and small touch displays
• Extensible UI with customizable workspace, widgets, and “pendant” remote-control UIs
• Watch-directory workflow to automatically detect and load new files
• Macros, command buttons, events, and features like Z-probe and tool-change workflows

Use Cases

• Running a CNC router or mill from a Raspberry Pi connected via USB serial
• Setting up a shop-floor touchscreen “pendant” interface for jogging and job control
• Managing CNC job preparation with file drop/watch-directory and repeatable macros

CNCjs is a practical choice when you want a browser-based control panel for hobbyist and prosumer CNC controllers, with visualization, extensibility, and multi-device access built in.