Why convert GeoJSON to TopoJSON?

TopoJSON stores shared borders between neighbouring shapes only once, so files with adjacent polygons, such as countries or districts, are usually much smaller. It is commonly used with D3.js and other web mapping libraries.

How do I read the TopoJSON in D3?

The features are stored in an object named "data". Load the file and call topojson.feature(topology, topology.objects.data) from the topojson-client library to get GeoJSON back for rendering.

How do I convert GeoJSON to TopoJSON?

Upload your GeoJSON file above, click Convert, and download the TopoJSON result instantly. No account or software needed.

Is converting GeoJSON to TopoJSON free?

Yes. It is free and unlimited for files up to 5 MB, with no account required. Larger files get 3 free conversions per day; beyond that, credit packs start at $1 and credits never expire.

Are my files stored or shared?

No. Files are processed in server memory and deleted immediately after conversion. Nothing is written to disk or retained.

Do I need to install anything?

No software installation needed. OmniConvert runs in the browser — just upload, convert, and download.

OmniConvert

Convert GeoJSON to TopoJSON

Free

Free and unlimited

For files up to 5 MB. No account needed. Larger files: 3 free per day.

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About this conversion

Convert GeoJSON to compact TopoJSON with shared borders for D3 and web maps. This converter processes your GeoJSON file server-side and returns a TopoJSON file instantly — no account, no software installation, and no file storage. Files are deleted from our servers immediately after conversion.

Learn more: GeoJSON file format explained

How to convert GeoJSON to TopoJSON

1. Upload — drag your GeoJSON file onto the converter above, or click to browse.
2. Convert — press Convert. Processing happens on secure servers in seconds.
3. Download — your TopoJSON file downloads automatically. No sign-up required.

Convert GeoJSON to TopoJSON from the command line

curl --fail-with-body \
  -H "Authorization: Bearer YOUR_TOKEN" \
  -F "file=@input.geojson" \
  -F "conversionId=geojson-to-topojson" \
  https://www.omniconvert.cloud/api/convert -o output.topojson

The API needs a token from a credit pack, and each API conversion uses one credit. Converting on this page stays free. API documentation

Frequently Asked Questions

Why convert GeoJSON to TopoJSON?: TopoJSON stores shared borders between neighbouring shapes only once, so files with adjacent polygons, such as countries or districts, are usually much smaller. It is commonly used with D3.js and other web mapping libraries.
How do I read the TopoJSON in D3?: The features are stored in an object named "data". Load the file and call topojson.feature(topology, topology.objects.data) from the topojson-client library to get GeoJSON back for rendering.
How do I convert GeoJSON to TopoJSON?: Upload your GeoJSON file above, click Convert, and download the TopoJSON result instantly. No account or software needed.
Is converting GeoJSON to TopoJSON free?: Yes. It is free and unlimited for files up to 5 MB, with no account required. Larger files get 3 free conversions per day; beyond that, credit packs start at $1 and credits never expire.
Are my files stored or shared?: No. Files are processed in server memory and deleted immediately after conversion. Nothing is written to disk or retained.
Do I need to install anything?: No software installation needed. OmniConvert runs in the browser — just upload, convert, and download.

No account needed · Credits never expire · Share your token link across devices