Check and fix laser SVG files

Find lines your laser would burn twice, lines too close together, specks and other problems before you cut, and download a repaired copy. Free, with nothing to install: your file is checked right here in your browser.

Choose an SVG

or drop it here

Advanced settings

Check (laserlint)

Line width

Width of a scored line. Default 0.10mm (--line).

Gap

Clear gap needed between the edges of two lines. Default 0.25mm (--gap).

Warn when lines are too close

Share of the line too close to other line that gives a warning. Default 1% (--warn-close).

Lines too close: problem above

Share of the line too close to other line that is a problem. Default 10% (--max-close).

Density: warn above

mm of line per mm² in the densest 10 mm area. Default 0.9 (--warn-density).

Density: problem above

mm of line per mm² in the densest 10 mm area. Default 2 (--max-density).

Smallest detail

Smallest closed shape that survives, across. Default 0.5mm (--detail).

Small details: problem above

How many closed shapes may be smaller than the smallest detail. Default 20 (--max-details).

Crossings: problem above

How many places score lines may cross. Default 50 (--max-crossings).

Line on other line: problem above

How much line may lie on other line. Default 2mm (--max-stacked).

Repair (laserfix)

Same line within

Lines nearer than this are the same line. Default 0.02mm (--same).

Join ends within

Ends nearer than this are joined. Default 0.05mm (--join).

Report gaps up to

Gaps wider than the join distance and up to this are reported, never closed. Default 1mm (--report-gaps).

Leave a setting empty to use its default. Lengths need a unit: mm, cm, in, pt or px.

How it works

Kinglet Preflight runs two free, open-source tools in your browser: laserlint checks the design, and laserfix repairs what it safely can, then measures the repaired copy again. They’re the same programs you can download and run on your computer.

Questions

Why does my laser cut some lines twice?

When two shapes share an edge, or a shape was pasted in place twice, the laser follows each shape, so the shared line burns twice: it chars the edge, widens the cut and wastes machine time. laserfix removes the copies and trims shared line from the later shape, so each line burns once.

Is my file uploaded?

No. Both tools run in your browser, and nothing sends your design anywhere. The page’s security policy blocks it from connecting anywhere but kinglet.dev, which it contacts only to load the tools: about 3 MB, the first time.

Which laser software does the repaired copy work with?

Any that opens SVG files, such as xTool Studio, LightBurn, Glowforge and LaserGRBL. laserfix only changes lines of the same color, because laser software picks its settings by color, and it keeps everything else in the file as it was.

What size is my design checked at?

At the size saved in the file, so scale it to the size you’ll burn first. The checks assume a 0.1 mm laser line and a 0.25 mm gap between lines; change them under Advanced settings.

Is it free?

Yes. laserlint and laserfix are open source under the MIT license, with their source on GitHub. You can also download them to check files on your computer.