Convert GeoJSON to FGB online
Convert GeoJSON — the open, web-native JSON format read by Leaflet, Mapbox and virtually every modern GIS tool — into FlatGeobuf, which is a fast, streamable binary format built for large datasets. Drop your GeoJSON file below, FGB is already selected as the output, and download the result. Everything runs in your browser and the cloud; you never install anything.
Upload your file
Drag and drop it into the converter below. A free account comes with three welcome conversions.
Convert in the cloud
MapGO detects the format and produces your download in seconds.
Download & keep it
Files are deleted automatically after 48 hours.
Files are deleted automatically after 48 hours. Your files are never shared.
Why convert GeoJSON to FGB with MapGO?
Most online converters take one file and hand back one file. MapGO is built on a real geospatial engine, so a single upload can do more.
- Several outputs in one upload
Tick FGB and any other formats you need; every selected format is delivered from the same file.
- Files up to 5 GB
Far beyond the browser-based converters that choke past a few hundred megabytes.
- Reproject while you convert
Set a source and target EPSG code and the coordinate system is changed during the conversion, no second tool needed.
- Private by default
Files are deleted automatically after 48 hours.
GeoJSON vs FGB at a glance
| GeoJSON | FGB | |
|---|---|---|
| Typical use | Web maps and APIs (Leaflet, Mapbox, D3); human-readable data in git | Large datasets streamed to web maps; cloud-native data pipelines |
| Size on disk | Verbose plain text — the largest of the common formats, but gzips well | Compact binary with a built-in spatial index |
| Attribute support | Flexible JSON properties — nesting and arrays allowed | Full attribute tables |
| Software support | Every modern GIS tool and every web mapping library | GDAL/QGIS, plus web libraries via the flatgeobuf JS package |
| Web-friendliness | Excellent — the native format of web mapping | Excellent — streams over plain HTTP range requests |
Other ways to convert GeoJSON to FGB
You don't need an online tool for this. If you have GDAL installed, one command does it.
In QGIS (free): open your GeoJSON via Layer → Add Layer, then right-click the layer → Export → Save Features As… and pick FGB as the format.
The MapGO converter above is for when you don't want to install anything, need to convert to several formats at once, or are handling files too large for a desktop machine.
ogr2ogr -f "FlatGeobuf" output.fgb input.geojsonGeoJSON to FGB: frequently asked questions
Is the GeoJSON to FGB converter free?
Partly. Every new account gets three welcome conversions for free, so you can try GeoJSON to FGB without paying. After that, you can either buy a credit pack and pay per conversion, or take a subscription, which gives you unlimited conversions within the plan's file-size limit. There is nothing to install; the whole conversion runs in the cloud.
Is my data kept private?
Conversion is fully automated and your file is never shared. Files are deleted automatically after 48 hours. Download your FGB result and it's yours to keep.
What does the FGB output contain?
You get a clean FlatGeobuf file with your geometry and attributes preserved, ready to open in the tools that read FGB.
Does my GeoJSON need to be in WGS84?
The GeoJSON spec (RFC 7946) defines coordinates as WGS84 longitude/latitude, and that is how MapGO reads it by default. If your file uses a different coordinate system, set the source EPSG code in the converter and MapGO applies it before converting.
What is FlatGeobuf actually good for?
It is a binary format with a built-in spatial index that web maps can stream over plain HTTP — the browser fetches only the features in view, no tile server required. Leaflet, MapLibre and OpenLayers read it via the flatgeobuf JavaScript package.
Can I convert FGB back to GeoJSON?
Yes — use our FGB to GeoJSON converter for the reverse direction. MapGO supports conversions in both directions between these formats.
Also convert
See it on the map first.
Open your GeoJSON in the workspace, check the shapes and attributes, then convert and download from the same place.