QLever KindSPARQL engine, triplestore, free and open-source softwareImplemented inC++LicenceApache Software License 2.0
Qooxdoo Kindsoftware library, JavaScript framework, free software, JavaScript libraryImplemented inJavaScriptLicenceGNU Lesser General Public License
Qt Kindwidget toolkit, software library, computing platform, free software, application frameworkImplemented inC++LicenceGNU General Public License, version 3.0, GNU General Public License, version 2.0, GNU Lesser General Public License, version 3.0
Quake engine Kindgame engineImplemented inGNU assembler, C, Assembly languageLicenceGNU General Public License, version 2.0 or later
QuakeSpasm Kindgame engine, source portLicenceGNU General Public License, version 2.0Based onFitzQuake
Quasar Framework Kindweb framework, free and open-source softwareLicenceMIT LicenseLatest version2.19.2 (March 26, 2026)
QuickTime Kindmultimedia framework, media player software, software development kitImplemented inCDeveloperApple Inc.
QuickTime X Kindmultimedia framework, media player software, software development kitImplemented inCDeveloperApple Inc.
Qwik Kindwidget toolkit, web framework, JavaScript framework, JavaScript libraryImplemented inTypeScriptLicenceMIT License