---
url: https://unstroke.vercel.app/reference/lower-level.md
description: >-
  The unstroke pipeline exposed piece by piece, from parsing SVG through
  flattening, stroking and union to path data, for tools that need geometry
  rather than markup.
---

# Lower-level API

The pipeline is exposed piece by piece, for tools that need the geometry
rather than the markup.

::: warning Stability
These exports follow the engine, not the public API. Their signatures and
the exact geometry they produce can change in a minor release, with a note
in the changelog. If you build on them, pin the minor version. The stable
surface is `outlineSvg`, `outlinePathData`, `outlineSvgToMultiPolygon`, the
[options](/reference/options) they accept, the warnings, and the CLI; those
only change in a major.
:::

```
parseSvg → shapes (segments + resolved style + transform)
parsePathData / transformSegments → normalized M / L / C / Z segments
flattenSegments → polylines
strokePolyline → polygons covering the stroke
unionRings / nonzeroRings / xorRings → merged multipolygon
multiPolygonToPathData → path data
```

If you just want the merged geometry, `outlineSvgToMultiPolygon` returns it as
a GeoJSON-style multipolygon, with the outer ring first and the holes after it.