# grbl/grbl

An open source, embedded, high performance g-code-parser and CNC milling controller written in optimized C that will run on a straight Arduino

Repository: https://github.com/grbl/grbl
Canonical: https://ross.abutalabs.com/products/grbl
Homepage: https://github.com/gnea/grbl/wiki
Language: C
License: NOASSERTION
License Family: other
Last push: 2024-06-02T19:33:15+00:00

## Health v2 (maintenance only)
Score: 32/100 (v2, computed 2026-09-03T02:20:16.233290+00:00)
- activity 0, release rhythm 35, longevity 100
- inputs: {"age_days": 6430, "days_push": 822, "days_rel": null, "gap_med": null, "n_releases_24m": 0}
- flags: no_releases, no_license
- formula: round(0.45*activity + 0.35*rhythm + 0.20*longevity); archived -> min(score, 10)

## Adoption (not part of the score)
Stars 6267, forks 3218 (observed 2026-08-28T04:09:41.155576+00:00)

## What it is
Grbl is an open-source, embedded, high-performance g-code parser and CNC milling controller written in optimized C for AVR microcontrollers, running on a plain Arduino Uno. It provides real-time motion control with acceleration planning and look-ahead for CNC mills, laser cutters, and similar machines.

## Use cases
- control a CNC milling machine with an Arduino
- parse and execute g-code on embedded hardware
- build a DIY laser cutter controller
- drive stepper motors with precise timing from a microcontroller
- add motion control to a homemade drawing machine
- replace parallel-port CNC motion control with low-cost hardware

## When to choose
- you need to run CNC motion control on minimal hardware like an ATmega328 Arduino
- you want a proven, widely supported g-code controller for hobby CNC or laser projects
- you need jitter-free step pulses up to 30kHz with look-ahead acceleration planning

## When to avoid
- you need active maintenance or new features - the project is discontinued since 2019
- you need modern 32-bit features, networking, or expanded I/O - consider grblHAL, FluidNC, or µCNC instead
- you need macro functions, variables, or canned cycles - Grbl expects GUIs to translate these into plain g-code

## Facets
- artifact type: library
- maturity: abandoned
- function: parser, embedded, interpreter
- domain: robotics, hardware, embedded-systems
- platform: embedded, c, iot
- tags: cnc, g-code, motion-control, arduino, avr, firmware, cnc-controller, stepper-motor, laser-cutter, 3d-printing, automation

## Member repositories
- grbl/grbl (main) score 32

## Provenance
- Observed fields: from GitHub, fetched 2026-08-28T04:09:41.155576+00:00.
- Health v2: computed from the inputs above; adoption is never an input.
- Inferred fields (summary, facets, guidance): AI-extracted, prompt v1, taxonomy v1, on 2026-08-29T17:46:29.933323+00:00, confidence not recorded.
  - readme: https://github.com/grbl/grbl (fetched 2026-08-28T04:09:41.155576+00:00, sha a4366cab146c)
  - homepage: https://github.com/gnea/grbl/wiki (fetched 2026-08-29T08:43:04.049785+00:00, sha e9fce575b7e0)
- Data as of 2026-08-30T08:39:29.467469+00:00.