TopoJSON to GeoJSON
LocalFree TopoJSON to GeoJSON converter in your browser — no upload, no sign-up. Restores full GeoJSON features from arcs; only the first object is converted.
Sample data loaded — click "Convert to GeoJSON" to try it.
What is it? TopoJSON to GeoJSON converts TopoJSON back into GeoJSON features — drop a .json/.topojson file (or paste); the success state names the converted object and a map preview accompanies the result. Everything runs locally in your browser — nothing is uploaded and no account is needed.
TL;DR: Convert TopoJSON to GeoJSON in your browser — free, no upload, no sign-up.
How to use
- Drop your .json/.topojson file into the input (or use "or load a file"), or paste the TopoJSON (a sample is pre-filled).
- Click "Convert to GeoJSON" (or press Ctrl/⌘+Enter).
- Check the converted-object summary and the map preview, then download the .geojson.
FAQ
Are all objects converted?
No — only the first object in the Topology's objects is converted; the success summary names it and reports the total object count. Multi-object files (e.g. US Atlas states + counties) need the object split out first.
Is it local?
Yes — parsing runs entirely in your browser; only the map preview's basemap tiles (CARTO) load over the network.
Does it preserve coordinate precision?
Output coordinates keep the source TopoJSON's quantization precision — nothing is rounded further on output.
What input files does it accept?
Any .json or .topojson file containing a TopoJSON topology, dropped into the input or pasted as text; a sample is pre-filled to try.
My TopoJSON has several objects — how do I convert a different one?
Only the first key under objects is converted. Move the object you need into the first position with a quick JSON edit in any text editor, or split the file first — atlas bundles that keep states and counties in one topology need this.
Will the output GeoJSON be larger than my TopoJSON?
Usually yes — and that is expected. TopoJSON saves space by storing each shared arc once; converting back gives every polygon its own copy of each boundary again, so the file returns to plain-GeoJSON size. Nothing is lost beyond the source's quantization rounding.
Do I need Python or topojson-client?
No — this does the equivalent of topojson-client's feature() in your browser, with nothing to install or upload. If you convert files inside a script every day, a two-line Python snippet is the right tool; this page is the zero-setup path for one-off files.
I need plain JSON, not GeoJSON — is this it?
Yes — GeoJSON is ordinary JSON, so the downloaded .geojson opens in any JSON parser; rename it to .json if a pipeline expects that extension.
Examples
- Drop or paste TopoJSON → get GeoJSON (the success state names the converted object)
Supported formats
Limitations
- Converts the first object in the Topology only — the success summary shows the selected object name and the total count; split multi-object files first.
- Large files are bounded by browser memory.
- Output coordinates keep the source TopoJSON's quantization precision.
- The map preview renders geometry locally (MapLibre); CARTO basemap tiles load over the network. Previews sample the first 5,000 features — the download contains all of them.
Privacy
Privacy first: this tool runs entirely in your browser — your input and files never leave your device, and everything is cleared when you close the page.