lcnc-suite — web UI for LinuxCNC

Hello everyone

I've been working on a web UI for LinuxCNC for my own use and thought I'd share it in case anyone finds it useful. Note that I'm not a professional programmer and this was largely AI-assisted, so take it for what it is.

Greetings

github.com/bildobodo/lcnc-suite.git

       







 

Looks impressive.

andypugh wrote:

Looks impressive.

+1

I really like this. Are you running your router/mill on your web UI?

Thank you all

Currently I am only running first tests on my machine. But mostly in sim. Still a lot of bug fixing to do. I was recently working on some performance improvements on the development branch which I will merge to main soon.

Looks fantastic. Its great seeing more UI options beyond Qt. Just curious, is the display optimized for touch or keyboard input?

Being more of a C/C++ person, I’ve been building a similar pet project focused on a C++ interface layer for LinuxCNC. The idea was to wrap both the NML and HAL polling sides in a clean, multi-client-safe bridge so the same core can support a WebSocket interface for remote clients and a Node.js addon for local UIs. The main goal is to decouple machine access from the frontend layer, making it possible to run multiple displays and control interfaces against a single machine. It's proving to be about as much work as I anticipated

rhscdn wrote:

Looks fantastic. Its great seeing more UI options beyond Qt. Just curious, is the display optimized for touch or keyboard input?

Being more of a C/C++ person, I’ve been building a similar pet project focused on a C++ interface layer for LinuxCNC. The idea was to wrap both the NML and HAL polling sides in a clean, multi-client-safe bridge so the same core can support a WebSocket interface for remote clients and a Node.js addon for local UIs. The main goal is to decouple machine access from the frontend layer, making it possible to run multiple displays and control interfaces against a single machine. It's proving to be about as much work as I anticipated

Don't stop this project.

Looks very nice, good job, keep it up

The trajectory of what gcode file of the maximum size can be visualized with acceptable performance? Or I’ll ask differently: how many segments are the maximum?

I was making a similar interface and ran into browser limitations in terms of memory, etc.

Hello Sandro,

Thank you for sharing lcnc-suite — it's a genuinely impressive piece of work, and the 3D toolpath preview alone saved me weeks of development time.

I'd like to report that I've successfully used lcnc-suite as the frontend for a **non-LinuxCNC** CNC system, in case it's useful to you or others here.

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**My Setup**

- SBC: Arduino UNO Q (Qualcomm QRB2210, Debian 13, Python 3.13)
- Motion controller: STM32U585 running grblHAL, connected via internal UART (ttyHS1)
- G-code interpreter: rs274ngc (from the linuxcnc-uspace package — the C extension only, no linuxcnc task/HAL)
- Machine: CoreXY pen plotter with CNC Shield V3

The key idea: instead of `import linuxcnc`, I wrote a custom FastAPI/asyncio gateway in Python that speaks the lcnc-suite WebSocket protocol on one side and rs274ngc + grblHAL on the other. This means lcnc-suite can work with backends other than LinuxCNC.

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**What works**

File upload, 3D toolpath preview, program execution (rs274ngc → grblHAL streaming), step execution, jog (continuous + incremental + diagonal), E-STOP/pause/resume/abort, WCS switching (G54–G59), spindle and coolant control, file browser — everything I've tried works well.

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**Undocumented requirements I found**

While building the gateway I hit a few things not covered in the README. Posting them here in case they help someone else attempting the same:

1. **`heartbeat` must return `{"type": "pong"}`** — any other response causes the WebSocket to disconnect after ~20 seconds.
2. **`GET /settings` is required on startup** — without it the UI enters a reload loop.
3. **`save_settings` WebSocket command must be handled** — sent frequently for jog speed etc., causes visible errors otherwise.
4. **`GET /gcode?path=...` is needed after upload** — the UI fetches file content via this endpoint to display in the editor.
5. **`GET /files` must return `FilesResponse` format** (`{ok, nc_dir, subdir, entries[]}`) — a plain array causes "No program files found".
6. **`status` broadcast must include `armed` field** — needed for the ON button to activate after ARM.

I've opened a GitHub issue with full details:
github.com/bildobodo/lcnc-suite/issues

The gateway source is here if anyone wants to look:
github.com/hoshigarasu/canon-grbl-bridge

Thanks again for building and sharing lcnc-suite.