Compare G-code files visually

The diff viewer puts two G-code files side by side and makes differences visible: both toolpaths are overlaid in the same 3D viewer, so changed moves, depths and feeds stand out in color. That way you check before the machine run whether a revised file really contains only the intended changes.

Typical use cases: checking a new program revision against the proven one, tracing the effect of changed parameters such as step-down or holding tabs, or making sure after a CAM or post-processor switch that the machine still runs the same paths.

The files are read and compared directly in the browser; nothing is uploaded to a server.

The diff viewer does not load in this view without JavaScript. Open www.step2gcode.com/diff in your browser.

What the diff viewer does

  • Overlay two G-code files in the same 3D viewer
  • Visual rendering of both toolpath revisions
  • Spot changes to feeds, depths and sequences
  • Entirely in the browser, no installation, no file upload

Frequently asked questions

Which differences does the diff viewer detect?

The diff viewer overlays the toolpaths of both files in the 3D viewer, so geometric changes such as a moved pocket, a different milling depth or additional paths become visible at a glance, without reading the code line by line. Changed feeds and sequences can be traced the same way.

Does the G-code have to come from step2gcode?

No. The diff viewer compares any G-code files, regardless of which CAM program or post-processor generated them. The only requirement is readable text G-code as processed by GRBL, Mach3 or LinuxCNC – the standard format of practically all hobby and workshop controllers.

Are my G-code files uploaded?

No. Both files are read and compared directly in the browser; nothing is uploaded to a server. That makes the diff viewer suitable even for programs that must not leave your machine, for example from ongoing customer projects.

Why would I need a G-code comparison?

Mainly as a safety net: when a proven program has been changed – new step-down, different holding tabs, another post-processor – the comparison shows whether only the intended spots really changed. That avoids the risky blind run of a new program revision on the workpiece.

Knowledge: What is G-code? Basics for CNC beginners