Examples

48 apps on 16 open-source libraries, from GDAL and OpenSSL to SQLite, compiled to WebAssembly by crossbind. Open one with your own files, and read the C++ and JavaScript behind it.

Geospatial

Open twenty vector formats and write seventeen, reprojected, in the pageGDALA terrain studio: hillshade, slope, contour lines and what is seen from where you clickGDALPixels to polygons: paint, and GDAL traces the shapesGDALFifteen geometry operations on shapes you can editGEOSFind out why a polygon is invalid, then repair it two waysGEOSSimplify a map without opening gaps between regionsGEOSWhere is this GeoTIFF?GeoTIFFGeoreference any pictureGeoTIFFRead heights and degrees off an elevation modelGeoTIFFSee what a map projection stretchesPROJFind out what a .prj is, and every way PROJ can transform itPROJWhy flights curve on a mapPROJ

Imaging

See what a photo gives away, then remove it without re-encodinglibjpeg-turboThe JPEG settings canvas.toBlob does not give youlibjpeg-turboDecode a 12 MP photo straight to a thumbnaillibjpeg-turboShrink an elevation model to the error you can acceptLERCLook inside a LERC tile before you decode itLERCWhere LERC beats gzip, and where it does notLERCOpen any TIFF, in any browserlibTIFFTurn page photos into one archival TIFFlibTIFFCompare every codec on 16-bit and float rasterslibTIFFSee what each WebP quality costs, and what it gives awayWebPTurn any picture into a sticker that fits the limitWebPWatch a WebP arrive, row by rowWebP

Database

Spatial SQL, with the answer drawn as a mapSpatiaLiteShortest paths in SQL, around the streets you closeSpatiaLiteA GeoPackage that QGIS and GDAL open, written in this tabSpatiaLiteSearch this site as you typeSQLiteAsk 50,000 points what is inside a boxSQLiteOpen any SQLite file, privatelySQLite

Crypto and TLS

Make a key and a certificate, or read any PEMOpenSSLA TLS handshake between two OpenSSL endpoints, in this tabOpenSSLOpen a .p12 or .pfx file, and make oneOpenSSL

Networking

Test a URL allowlist against libcurl's own parsercURLTake a URL apart the way libcurl does, beside your browsercURLRead HTTP dates the way curl doescURL

Text

Parse a gigabyte of XML without holding itExpatBillion laughs, blocked at a line and columnExpatRead a GPS track, heart rate and allExpatRepair text that was opened with the wrong encodingiconvWrite the exact bytes a legacy system importsiconvRead the encodings TextDecoder refusesiconv

Compression

Jump into the middle of a big .gz without unzipping itzlibMake a PNG smaller without changing a pixelzlibLook inside a .zip, .docx or .xlsx without unpacking itzlibTeach zstd your data, then watch small messages shrinkZstandardSend a 1 MB update in about 1 KBZstandardLook inside a .tar.zst without unpacking itZstandard