About Reproj

Your files never leave your machine

There is no upload. When you drop a file on Reproj, it is read and converted by GDAL compiled to WebAssembly, running locally in your browser tab. The only network requests Reproj makes during a conversion are for its own program files and, when a datum transformation needs one, an official grid-shift file — requests that carry none of your data. Close the tab and nothing persists anywhere.

This isn't a policy promise that requires trust — it's how the tool is built. You can verify it in your browser's network inspector: convert a file and watch nothing be uploaded.

Accuracy

Coordinate transformations use PROJ, the same engine behind QGIS and most professional GIS software, with official datum distortion grids fetched on demand (NADCON, OSTN15, GDA2020 conformal, and the rest of the PROJ grid registry). Every conversion includes a transformation report stating which method was used and its published accuracy.

Built on open source

Reproj stands on the shoulders of exceptional open-source projects: GDAL/OGR (MIT/X licence), PROJ (MIT licence), gdal3.js (LGPL), and MapLibre GL JS (BSD). Grid-shift files are published by national geodetic agencies and distributed via the PROJ CDN under open licences.

Contact

Found a file that converts wrongly, or a format you need? hello@reproj.io