Geometry, faithfully
Points, lines and polygons come across with their vertex order intact, and rings are wound the way the target format expects.
Convert GeoJSONSeq to TopoJSON Online
Convert GeoJSONSeq files to TopoJSON in your browser. Newline-delimited GeoJSON, one feature per line, for streaming becomes a compact GeoJSON variant that shares boundaries between neighbours, with nothing uploaded to a server.
GeoJSONSeq from
TopoJSON to
Drag a GeoJSONSeq file here
or
Accepts .geojsonl, .ndjson, .geojsons · no size limit · nothing is uploaded
POSMove over the map to read coordinates
How to convert GeoJSONSeq to TopoJSON
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1
Choose your GeoJSONSeq file
Drag it onto the panel or browse for it. Several files at once is fine, and each is read straight from your disk rather than uploaded.
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2
Check the preview
Features draw on a map with their attributes. A polygon that came through inside out, or a file that turns out to be empty, shows up here rather than later in QGIS.
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3
Download the TopoJSON
Press download and the file is written straight to your downloads folder. Adjust precision or other settings first if you need to.
What comes across
GeoJSONSeq carries more than geometry, and most converters drop the rest. This one does not.
Attributes with their types
Fields become properties with numbers kept as numbers, so you can filter and style on them the moment the file opens.
A preview before you commit
Features draw on a map with their attributes, so a file that turns out to be empty or misplaced shows up here rather than three steps later in QGIS.
Frequently asked questions
Is my file uploaded anywhere?
No. The conversion runs as JavaScript in your own browser. The file is read from disk, converted in memory and saved back to your downloads folder. Nothing is transmitted, which is what makes this safe for survey and revenue data.
What file size can I convert?
Roughly 100 to 150 MB comfortably, and more on a stronger machine. There is no server quota and no daily cap, because the work happens on your device rather than ours.
Will attributes survive the conversion?
Yes. Attribute values are carried across with their types intact wherever the target format supports them, so numbers stay numbers and text stays text.
Do I need an account?
No. There is no sign-up, no email address and no watermark. Open the page, drop a file, download the result.
What coordinate system does the output use?
WGS 84 (EPSG:4326) in decimal degrees, which is what web mapping tools expect. Where the source file declares its own CRS, that is read and reported before conversion.
All our converters
Every conversion below is live. Pick a starting format and go.
GeoJSON
KML
KMZ
GPX
CSV
Excel
Shapefile
WKT
TopoJSON
GeoJSONSeq
DXF
SVG is an export format only — you can convert any layer into it, but not back out again. A drawn map has no coordinates to recover, only shapes on a page.