GeoJSON & Shapefile Validator

Upload a GeoJSON or a Shapefile and check whether every geometry is valid under the Simple Features model — with the reason for each error and an optional automatic repair you can download. Free, runs entirely in your browser: the file never leaves your computer.

Upload a file — .geojson, or a shapefile as a single .zip or as .shp/.dbf/.shx selected together — and find out whether every geometry is valid. If it isn’t, the exact reason; if you want, we’ll fix it and you can download the result.

Tip

Private by design. Your file is processed entirely in your browser (Python via WebAssembly) — it’s never uploaded to any server, including ours. Nothing to configure, nothing to trust: the code never gets the chance to see your data.

The code itself isn’t shown here — it’s a fixed, non-editable check using Shapely/GEOS underneath; see the full article for the actual code, editable and explained line by line.

make_valid() rebuilds the geometry into an equivalent, valid form — reuses exactly the data just diagnosed above, no new reading of the file.

First run loads the Python engine — expect about a minute. Instant after that, and again each time you come back to this page.

Want to understand what makes a geometry invalid, see the actual code, or compare against R’s independent implementation? The full article uses this same engine with a gallery of common errors explained one by one.