Free Software packages using GEOS

• ​PostGIS (C API)
• ​MapServer (C API)
• ​Quantum GIS (C API)
• ​OGR (C API)
• ​GRASS (C API)
• ​Shapely (C API)
• ​INGRES (C API)
• ​SpatiaLite (C API)
• ​MapGuide Open Source
• ​GeoDjango (C API)
• ​MapWindow GIS (C API)
• ​Osmium Library (C++ API <3.6)
• ​osgEarth (C++ API)
• ​MonetDB (C API)
• ​rgeos (C API)
• ​SYNTHESE (C++ API)
• ​Zgel (Ruby API)
• ​geoPHP (PHP API)
• ​node-geos (C++ API)
• ​RT Topology Library (C API)

Proprietary packages using GEOS

• ​FME
• ​Autodesk MapGuide Enterprise

Software that previously used geos

• ​osm2pgsql (C++ API <3.6)