100% local — files never leave your device
Convert TopoJSON to NDJSON
Turn TopoJSON into GeoJSON Lines (NDJSON) instantly in your browser. No upload, no account, and no file ever crosses the network.
About TopoJSON
Quantized topology used by D3 and web cartography.
- Export quantizes coordinates and writes one arc per ring; arcs are not deduplicated.
About GeoJSON Lines (NDJSON)
One GeoJSON feature per line. Streams well into BigQuery, DuckDB and Athena.
Step by step
How to convert TopoJSON to NDJSON
- 01
Drop your .topojson file
Open the converter and drop the TopoJSON file — parsing happens locally in a Web Worker, so nothing is uploaded.
- 02
Choose NDJSON as the output
Pick NDJSON, reproject to any of 180+ coordinate systems if needed, trim attributes and preview the geometry on a map.
- 03
Download the .ndjson file
Save a single file, or convert a whole batch and download everything as a ZIP. Nothing is stored after the download.
TopoJSON to NDJSON — questions
Is converting TopoJSON to NDJSON really private?
Yes. The conversion runs entirely in your browser using a Web Worker — the TopoJSON file is never sent to a server, so it works with confidential data and offline.
Do I need an account to convert TopoJSON to NDJSON?
No. There is no signup, no email and no install. Open the converter, drop the file and download the result.
What happens to attributes and coordinate systems?
Attributes are carried across into the GeoJSON Lines (NDJSON) output. You can also reproject between 180+ coordinate reference systems or add a custom proj4 definition before writing.
Need the other direction? Convert NDJSON to TopoJSON