This is a list of free and open-source software packages, computer software licensed under free software licenses and open-source licenses. Software that fits the Free Software Definition may be more appropriately called free software; the GNU project in particular objects to their works being referred to as open-source.^[1] For more information about the philosophical background for open-source software, see free software movement and Open Source Initiative. However, nearly all software meeting the Free Software Definition also meets the Open Source Definition and vice versa. A small fraction of the software that meets either definition is listed here. Some of the open-source applications are also the basis of commercial products, shown in the List of commercial open-source applications and services.

Artificial intelligence

General AI

• OpenCog – A project that aims to build an artificial general intelligence (AGI) framework. OpenCog Prime is a specific set of interacting components designed to give rise to human-equivalent artificial general intelligence.

Computer vision

• AForge.NET – computer vision, artificial intelligence and robotics library for the .NET framework
• OpenCV – computer vision library in C++

Machine learning

• See List of open-source machine learning software
• See Data Mining below
• See R programming language – packages of statistical learning and analysis tools

Planning

• TREX – Reactive planning

Robotics

• Robot Operating System (ROS)
• Webots – Robot simulator
• YARP – Yet Another Robot Platform

Assistive technology

Speech (synthesis and recognition)

• CMU Sphinx – Speech recognition software from Carnegie Mellon University
• Emacspeak – Audio desktop
• ESpeak – Compact software speech synthesizer for English and other languages
• Festival Speech Synthesis System – General multilingual speech synthesis
• Modular Audio Recognition Framework – Voice, audio, speech NLP processing
• NonVisual Desktop Access – (NVDA) Screen reader, for Windows
• Text2Speech – Lightweight, easy-to-use Text-To-Speech (TTS) Software

Other assistive technology

• Dasher – Unique text input software
• Gnopernicus – AT suite for GNOME 2
• Virtual Magnifying Glass – A multi-platform screen magnification tool

CAD

• FreeCAD – Parametric 3D CAD modeler with a focus on mechanical engineering, BIM, and product design.
• LibreCAD – 2D CAD software using AutoCAD-like interface and file format.
• SolveSpace – 2D and 3D CAD, constraint-based parametric modeler with simple mechanical simulation abilities.
• BRL-CAD – a constructive solid geometry (CSG) solid modeling computer-aided design (CAD) system.
• OpenSCAD – A scripting based 3D CAD software.
• Open Cascade Technology (OCCT) – a CAD kernel for 3D CAD, CAM, CAE, etc.
• Blender
• Wings 3D
• Art of Illusion
• MeshLab
• MakeHuman
• Sweet Home 3D

Finite Element Analysis (FEA)

• Gmsh – A three-dimensional finite element mesh generator with built-in pre- and post-processing facilities.

Electronic design automation (EDA)

• Fritzing – a CAD software for the design of electronics hardware to build more permanent circuits from prototypes
• KiCad – a suite for electronic design automation (EDA) for schematic capture, PCB layout, manufacturing file viewing, SPICE simulation, and engineering calculation

Computer simulation

• Blender – 3D computer graphics software toolset used for creating animated films, visual effects, art, 3D printed models, and motion graphics.
• OpenFOAM – open-source software used for computational fluid dynamics (or CFD).
• FlightGear - atmospheric and orbital flight simulator with a flight dynamics engine (JSBSim) that is used in a 2015 NASA benchmark^[2] to judge new simulation code to space industry standards.
• SimPy – Queue-theoretic event-based simulator written in Python
• Salome – a generic platform for Pre- and Post-Processing for numerical simulation

Cybersecurity

Antivirus

• ClamAV – cross-platform antimalware toolkit written in C and C++, able to detect many types of malware including viruses
• ClamWin – free and open-source antivirus tool for Windows and written in C, C++
• Lynis – Security audit tool (set of shell scripts) for Unix and Linux

Data loss prevention

• MyDLP

Data recovery

• dvdisaster
• ddrescue
• Foremost
• PhotoRec
• TestDisk

Forensics

• The Coroner's Toolkit
• The Sleuth Kit

Anti-forensics

• USBKill
• Tails
• BusKill

Disk erasing

• DBAN
• srm

Encryption

• AES
• Bouncy Castle
• GnuPG
• GnuTLS
• KGPG
• NaCl
• OpenSSL
• Seahorse
• Signal
• stunnel
• TextSecure
• wolfCrypt
• 7-Zip

Disk encryption

• dm-crypt
• CrossCrypt
• FreeOTFE and FreeOTFE Explorer
• eCryptfs
• VeraCrypt

Firewall

• Firewalld
• Uncomplicated Firewall (ufw)
• Firestarter
• IPFilter
• ipfw
• iptables
• nftables
• M0n0wall
• PeerGuardian
• PF
• pfSense
• OPNsense
• Rope
• Shorewall
• SmoothWall
• Vyatta
• VyOS

Network and security monitoring

• Snort – Network intrusion detection system (IDS) and intrusion prevention system (IPS)
• OpenVAS – software framework of several services and tools offering vulnerability scanning and vulnerability management

Secure Shell (SSH)

• Cyberduck – macOS and Windows client (since version 4.0)
• Lsh – Server and client, with support for SRP and Kerberos authentication
• OpenSSH – Client and server
• PuTTY – Client-only

Password management

• Bitwarden
• KeePass
• KeePassXC (multiplatform fork able to open KeePass databases)
• Password Safe
• Mitro
• Pass

Other cybersecurity programs

Data storage and management

Backup software

Database management systems (including administration)

• Apache Cassandra – A NoSQL database from Apache Software Foundation offers support for clusters spanning multiple datacenter
• Apache CouchDB – A NoSQL database from Apache Software Foundation with multi-master replication
• MariaDB – A community-developed relational database management system with pluggable storage engines and commercial support
• PostGIS – Adds support for geographic objects to the PostgreSQL as per Open Geospatial Consortium (OGC)
• PostgreSQL – A relational database management system emphasizes on extensibility and SQL compliance and available for Windows, Linux, FreeBSD, and OpenBSD

Data mining

• Environment for DeveLoping KDD-Applications Supported by Index-Structures (ELKI) – Data mining software framework written in Java with a focus on clustering and outlier detection methods
• FrontlineSMS – Information distribution and collecting via text messaging (SMS)
• Konstanz Information Miner (KNIME)
• OpenNN – Open-source neural network software library written in C++
• Orange (software) – Data visualization and data mining for novice and experts, through visual programming or Python scripting. Extensions for bioinformatics and text mining
• RapidMiner – Data mining software written in Java, fully integrating Weka, featuring 350+ operators for preprocessing, machine learning, visualization, etc. – the prior version is available as open-source
• Scriptella ETL – ETL (Extract-Transform-Load) and script execution tool. Supports integration with J2EE and Spring. Provides connectors to CSV, LDAP, XML, JDBC/ODBC, and other data sources
• Weka – Data mining software written in Java featuring machine learning operators for classification, regression, and clustering
• JasperSoft – Data mining with programmable abstraction layer

Data Visualization Components

• ParaView – Plotting and visualization functions developed by Sandia National Laboratory; capable of massively parallel flow visualization utilizing multiple computer processors
• VTK – Toolkit for 3D computer graphics, image processing, and visualisation.

Digital Asset Management software system

Disk partitioning software

• GParted
• FIPS (computer program)
• TestDisk

Enterprise search engines

• ApexKB, formerly known as Jumper
• Lucene
• Nutch
• Solr
• Xapian

ETLs (Extract Transform Load)

• Konstanz Information Miner (KNIME)
• Pentaho

File archivers

• PeaZip
• 7-Zip

File systems

• OpenAFS – Distributed file system supporting a very wide variety of operating systems
• Tahoe-LAFS – Distributed file system/Cloud storage system with integrated privacy and security features
• CephFS – Distributed file system included in the Ceph storage platform.

Desktop publishing

• Collabora Online Draw and Writer – Enterprise-ready edition of LibreOffice accessible from a web browser. The Draw application is for flyers, newsletters, brochures and more, Writer has most of the functionality too.^[3]
• Scribus – Designed for layout, typesetting, and preparation of files for professional-quality image-setting equipment. It can also create animated and interactive PDF presentations and forms.
• LyX – A "What You See Is What You Mean" document creation system, LyX makes use of the LaTeX markup macro system for TeX, allowing the elegant creation of documents which match up with the layouts in it for various document classes.

E-book management and editing

• Calibre – Cross-platform suite of ebook software
• Collabora Online Writer – Enterprise-ready edition of LibreOffice accessible from a web browser. Allows exporting in the EPUB format.^[4]
• Sigil – Editing software for e-books in the EPUB format

Education

E-learning, learning support

• ATutor – Web-based Learning Content Management System (LCMS)
• Chamilo – Web-based e-learning and content management system
• Claroline – Collaborative Learning Management System
• DoceboLMS – SAAS/cloud platform for learning
• eFront – Icon-based learning management system
• H5P – Framework for creating and sharing interactive HTML5 content
• IUP Portfolio – Educational platform for Swedish schools
• ILIAS – Web-based learning management system (LMS)
• Moodle – Free and open-source learning management system
• OLAT – Web-based Learning Content Management System
• Omeka – Content management system for online digital collections
• openSIS – Web-based Student Information and School Management system
• Sakai Project – Web-based learning management system
• SWAD – Web-based learning management system

Academic advising

• FlightPath – Academic advising software for universities

Educational suites for children

• Tux Paint – Painting application for 3–12 year olds
• GCompris – Educational entertainment, aimed at children aged 2–10

Language

• Alpheios Project
• Anki (software)
• FirstVoices
• Kiten

Operating systems

• UberStudent – Linux-based operating system and software suite for academic studies
• MAX (operating system)
• Edubuntu

Mind mapping & others

• Vym (software)
• Compendium (software)
• Gnaural – Brainwave entrainment software

Offline learning & Open data

• Kiwix: A free and open-source offline web browser that allows users download Wikipedia entire content and use for offline learning, later was expanded with repositories for Wikimedia Foundation, public domain texts from Project Gutenberg, many of the Stack Exchange sites, and other resources.
• OpenStreetMap: OpenStreetMap was developed in 2004, it uses Open data and users data input through Crowdsourcing and Web mapping to create a complete and downloadable alternative to other online maps, this allow users to enter data when there is no data available due to lack of governance and economic interest or due lower population of the places mapped

Typing

• KTouch – Touch typing lessons with a variety of keyboard layouts
• Tux Typing – Typing tutor for children, featuring two games to improve typing speed

File managers

Finance

Accounting

• GnuCash – Double-entry book-keeping
• HomeBank – Personal accounting software
• KMyMoney – Double-entry book-keeping
• LedgerSMB – Double-entry book-keeping
• RCA open-source application – management accounting application
• SQL Ledger – Double-entry book-keeping
• TurboCASH – Double-entry book-keeping for Windows
• Wave Accounting – Double-entry book-keeping

Cryptocurrency

• Bitcoin – Blockchain platform, peer-to-peer decentralised digital currency
• Ethereum – Blockchain platform with smart contract functionality

CRM

• CiviCRM – Constituent Relationship Management software aimed at NGOs
• iDempiere – Business Suite, ERP and CRM
• SuiteCRM – Web-based CRM

ERP

• Adempiere – Enterprise resource planning (ERP) business suite
• Apache OFBiz – A suite of enterprise applications from Apache Software Foundation
• Compiere – ERP solution automates accounting, supply chain, inventory, and sales orders
• Dolibarr – Web-based ERP system
• ERPNext – Web-based open-source ERP system for managing accounting and finance
• ERP5 – Single Unified Business Model based system written with Python and Zope
• iDempiere – Fully navigable on PCs, tablets and smartphones driven only by a community of supporters
• Ino erp – Dynamic pull based system ERP
• JFire – An ERP business suite written with Java and JDO
• LedgerSMB – A double entry accounting and ERP system written with Perl
• metasfresh – ERP Software
• Odoo – Open-source ERP, CRM and CMS
• Openbravo – Web-based ERP
• Tryton – Open-source ERP

Human resources

• OrangeHRM – Commercial human resource management

Microfinance

• Cyclos – Software for microfinance institutions, complementary currency systems and timebanks
• Mifos – Microfinance Institution management software

Process management

• Bonita Open Solution – Business Process Management

Trading

• QuickFIX – FIX protocol engine written in C++ with additional C#, Ruby, and Python wrappers
• QuickFIX/J – FIX protocol engine written in Java

Games

Action

• OpenArena – First-person shooter.
• Xonotic – First-person shooter that runs on a heavily modified version of the Quake engine known as the DarkPlaces engine
• Warsow – First-person shooter fast-paced arena FPS game that runs on the Qfusion engine

Application layer

• WINE – Allows Windows applications to be run on Unix-like operating systems

Chess

• ChessV
• Fairy-Max
• GNU Chess
• PyChess
• XBoard
• Lichess

Educational games

• Tux, of Math Command
• Tux Paint

Video game emulation

• MAME – Multi-platform emulator designed to recreate the hardware of arcade game systems
• MESS – Multi-platform emulator designed to recreate the hardware of video game consoles
• RetroArch – Cross-platform front-end for emulators, game engines and video games
• Snes9x – A Super Nintendo emulator
• Stella – Atari 2600 emulator
• PCSX – A PlayStation emulator designed to recreate the hardware of the original PlayStation system
• PCSX2 – A PlayStation 2 emulator designed to recreate the hardware of PlayStation 2 system
• PPSSPP – A PlayStation Portable emulator designed to recreate the hardware of PlayStation Portable system
• Project64 – A Nintendo 64 emulator
• RPCS3 – A PlayStation 3 emulator designed to recreate the hardware of PlayStation 3 system
• Dolphin (emulator) – A GameCube and Wii emulator designed to recreate the hardware of GameCube and Wii systems
• Citra (emulator) – A Nintendo 3DS and Wii emulator designed to recreate the hardware of Nintendo 3DS systems
• Cemu – A Wii U emulator designed to recreate the hardware of Wii U systems

Music video games

• Frets on Fire

Karaoke

• UltraStar

Rhythm game

• StepMania

Puzzle

• Pingus – Lemmings alternative with penguins instead of lemmings.

Sandbox

• Minetest – An open source voxel game engine.

Snake games

• GLtron

Simulation

• OpenTTD – Business simulation game in which players try to earn money via transporting passengers and freight by road, rail, water and air.
• SuperTuxKart – Kart racing game that features mascots of various open-source projects.
• FlightGear – Flight simulator.

Strategy

• 0 A.D. – Real-time strategy video game
• Freeciv – Turn-based strategy game inspired by proprietary Sid Meier's Civilization series
• Glest
• The Battle for Wesnoth – Turn-based strategy video game with fantasy setting

Genealogy

• Gramps (software) – a free and open source genealogy software

Geographic information systems

• QGIS – cross-platform desktop geographic information system (GIS) application to view, edit, and analyse geospatial data

Graphical user interface

Desktop environments

Window managers

Windowing system

Groupware

Content management systems

Wiki software

Healthcare software

Integrated library management software

• Evergreen – Integrated Library System initially developed for the Georgia Public Library Service's PINES catalog
• Koha – SQL-based library management
• NewGenLib
• OpenBiblio
• PMB
• refbase – Web-based institutional repository and reference management software

Image editor

• Darktable – Digital image workflow management, including RAW photo processing
• digiKam – Integrated photography toolkit including editing abilities
• GIMP – Raster graphics editor aimed at image retouching/editing
• Inkscape – Vector graphics editor
• Karbon – Scalable vector drawing application in KDE
• Krita – Digital painting, sketching and 2D animation application, with a variety of brush engines
• LazPaint – Lightweight raster and vector graphics editor, aimed at being simpler to use than GIMP
• LightZone – Free, open-source digital photo editor software application.
• RawTherapee – Digital image workflow management aimed at RAW photo processing

Maps & Navigation

• OpenStreetMap – open geographic database updated and maintained by a community of volunteers via open collaboration.

Mathematics

• ALTRAN
• FriCAS
• GAP (computer algebra system)
• GiNaC
• gnuplot
• Maxima
• Mathomatic
• Normaliz
• SageMath
• Singular (software)
• SymPy
• Yacas

Computer algebra systems

• Axiom
• Cadabra
• Cambridge Algebra System
• CPMP-Tools
• CoCoA
• Erable
• PARI/GP
• Reduce
• Xcas

symbolic manipulation systems

• FORM (symbolic manipulation system)

Mobile software

• Celestia (Android, iOS)
• Calligra (Android)
• Collabora Online Libre office for online collaboration and mobile devices. (Android)
• Kiwix: Offline web browser that allows users to download the entire content of Wikipedia for offline learning purposes. (Android)
• Krita (Android)
• Maps.me (Android)
• Organic Maps (Android, iOS)
• OsmAnd (Android)
• Stellarium (Android, iOS)
• Tor Browser – onion-routed browser by The Tor Project, based on Firefox ESR
• VLC (Android, iOS)
• Wikipedia (Android, iOS) – See also: List of Wikipedia mobile applications

Statistics

• R – Statistics software

Numerical analysis

• Octave – Numerical analysis software
• Scilab – Numerical analysis software

Geometry

• Geogebra – Geometry and algebra

Spreadsheet

• LibreOffice Calc – spreadsheet component of the LibreOffice package
• Gnumeric – spreadsheet program of the GNOME Project
• Calligra Sheets – spreadsheet component of the Calligra Suite in KDE
• Pyspread – spreadsheet which uses Python for macro programming, and allows each cell to contain data, the results of a calculation, a Python program, or the results of a Python program.

Media

Audio editors, audio management

• Audacity
• Ardour: Professional digital audio workstation
• LMMS: Digital audio workstation

CD/USB-writing software

• Brasero (software)
• cdrtools
• K3b
• X-CD-Roast

Flash animation

• Pencil2D – For animations
• SWFTools – For scripting

Game engines

• Blender Game Engine – Discontinued 2019
• Godot – Application for the design of cross-platform video games
• MonoGame – C# framework
• Open3DEngine – Based on Amazon Lumberyard
• Stride – (prev. Xenko) 2D and 3D cross-platform game engine originally developed by Silicon Studio

Chess engines

• KnightCap
• Leela Chess Zero – Universal Chess Interface chess engine
• Stockfish – Universal Chess Interface chess engine

Graphics

2D

• Pencil2D – Simple 2D graphics and animation program
• Synfig – 2D vector graphics and timeline based animation
• TupiTube (formerly KTooN) – Application for the design and creation of animation
• OpenToonz – Part of a family of 2D animation software
• Krita – Digital painting, sketching and 2D animation application, with a variety of brush engines
• Blender – Computer graphics software, Blender's Grease Pencil tools allow for 2D animation within a full 3D pipeline.
• mtPaint – raster graphics editor for creating icons, pixel art

3D

• Blender – Computer graphics software featuring modeling, sculpting, texturing, rigging, simulation, rendering, camera tracking, video editing, and compositing
• MakeHuman
• OpenFX – Modeling and animation software with a variety of built-in post processing effects
• Seamless3d – Node-driven 3D modeling software
• Wings 3D – subdivision modeler inspired by Nendo and Mirai from Izware.

Image galleries

• Shotwell

Image viewers

• Eye of GNOME
• F-spot
• feh
• Geeqie
• Gthumb
• Gwenview
• KPhotoAlbum
• Opticks

Multimedia codecs, containers, splitters

Subtitle

• Aegisub
• Gnome Subtitles
• Subtitle Composer (KDE)
• Subtitle Edit

Television

Video converters

• Dr. DivX
• FFmpeg
• MEncoder
• OggConvert

Video editing

• Avidemux
• AviSynth
• Blender
• Cinelerra
• Flowblade
• Kdenlive
• Kino
• LiVES
• LosslessCut
• Natron
• Olive
• OpenShot
• Open Movie Editor
• Pitivi
• Shotcut
• VirtualDub
• VirtualDubMod
• VideoLAN Movie Creator

DVD authoring

• DeVeDe
• DVD Flick
• DVDStyler

Other media packages

• Celtx – Media pre-production software
• Open Broadcaster Software (OBS) – Cross-platform streaming and recording program

Ripping

• K9Copy
• Thoggen

Video encoders

• Avidemux
• HandBrake
• FFmpeg
• OggConvert

Video players

• Media Player Classic
• VLC media player
• mpv

Networking and Internet

Advertising

• Revive Adserver

Communication-related

• Asterisk – Telephony and VoIP server
• Ekiga – Video conferencing application for GNOME and Microsoft Windows
• ConferenceXP – video conferencing application for Windows XP or later
• FreePBX – Front-end and advanced PBX configuration for Asterisk
• FreeSWITCH – Telephony platform
• Jami – Cross-platform, peer to peer instant-messaging and video-calling protocol that offers end-to-end encryption and SIP client
• Jitsi – Java VoIP and Instant Messaging client
• QuteCom – Voice, video, and IM client application
• Enterprise Communications System sipXecs – SIP Communications Server
• Slrn – Newsreader
• Telegram
• Twinkle – VoIP softphone
• Tox – Cross-platform, peer-to-peer instant-messaging and video-calling protocol that offers end-to-end encryption

E-mail

• Amavis – Email content filter
• Claws Mail – Email Client
• Fetchmail – Email Retrieval
• Geary – Email client based on WebKitGTK+
• GNUMail – Cross-platform email client
• Hula – Discontinued mail and calendar project
• K-9 Mail – Android Email Client
• MailScanner – Email security system
• MH Message Handling System – Email Client
• Modest – Email Client
• Mozilla Mail & Newsgroups – Email Client that was part of the now discontinued Mozilla Application Suite
• Mozilla Thunderbird – Email, news, RSS, and chat client
• POPFile – Cross-platform mail filter
• Roundcube – Web-based IMAP email client
• Sylpheed – Email and News Client
• Sympa – MLA software
• Vpopmail – Email management software

File transfer

Grid and distributed processing

• GNU Queue
• HTCondor
• pexec

Instant messaging

IRC Clients

Middleware

• Apache Axis2 – Web service framework (implementations are available in both Java & C)
• Apache Geronimo – Application server
• Bonita Open Solution – a J2EE web application and java BPMN2 compliant engine
• GlassFish – Application server
• Apache Tomcat – Servlet container and standalone webserver
• JBoss – Application server
• ObjectWeb JOnAS – Java Open Application Server, a J2EE application server
• OpenRemote – IoT Middleware
• TAO (software) – C++ implementation of the OMG's CORBA standard
• Enduro/X – C/C++ middleware platform based on X/Open group's XATMI and XA standards

RSS, Atom readers, aggregators

• Akregator – Platforms running KDE
• Liferea – Platforms running GNOME
• NetNewsWire – macOS, iOS
• RSS Bandit – Windows, using .NET framework
• RSSOwl – Windows, macOS, Solaris, Linux using Java SWT Eclipse
• Sage (Mozilla Firefox extension)

Peer-to-peer file sharing

• Popcorn Time – Multi-platform, free, and open-source media player
• qBittorrent – Alternative to popular clients such as μTorrent
• Transmission – BitTorrent client

Portal Server

• Drupal
• Liferay
• Sun Java System Portal Server
• uPortal

Remote access and management

• FreeNX
• OpenVPN
• rdesktop
• Synergy
• VNC (RealVNC, TightVNC, UltraVNC)
• Remmina (based on FreeRDP)

Routing software

Web browsers

Graphical

• Chromium – web browser using the custom Blink engine from which Google Chrome draws its source code
• Brave – privacy-focused web browser based on Chromium browser
• Falkon – web browser based on Blink engine, a KDE project
• Firefox – Mozilla-developed web browser using Gecko layout engine
• Waterfox – Firefox fork supporting legacy extensions, 64-bit only
• Pale Moon – a customizable fork of Firefox
• Tor Browser – onion-routed browser by The Tor Project, based on Firefox ESR
• GNOME Web – WebKit-based web browser for the GNOME desktop environment
• Midori – Lightweight web browser using the WebKit layout engine
• qutebrowser – keyboard operated Webkit-based browser with vi-like keybindings
• SeaMonkey Navigator – the SeaMonkey internet suite's web browser
• Surf – a minimal tab-less browser by suckless.org using WebKitGTK
• Firefox Focus – privacy-focused mobile web browser from Mozilla available for Android and iOS

Text-based

• Lynx – a text-based web browser developed since 1992
• Links – a text-based browser with a framebuffer-based graphical mode
• ELinks – fork of Links with JavaScript support

Webcam

• Cheese – GNOME webcam application
• Guvcview – Linux webcam application

Webgrabber

• cURL
• HTTrack
• Wget

Web-related

• Apache Cocoon – A web application framework
• Apache – The most popular web server
• AWStats – Log file parser and analyzer
• BookmarkSync – Tool for browsers
• Caddy – an extensible, cross-platform, open-source web server written in Go.
• Cherokee – Fast, feature-rich HTTP server
• curl-loader – Powerful HTTP/HTTPS/FTP/FTPS loading and testing tool
• FileZilla – FTP
• Hiawatha – Secure, high performance, and easy-to-configure HTTP server
• HTTP File Server – User-friendly file server software, with a drag-and-drop interface
• lighttpd – Resource-sparing, but also fast and full-featured, HTTP Server
• Lucee – CFML application server
• Nginx – Lightweight, high performance web server/reverse proxy and e-mail (IMAP/POP3) proxy
• NetKernel – Internet application server
• Qcodo – PHP5 framework
• Squid – Web proxy cache
• Vaadin – Fast, Java-based framework for creating web applications
• Varnish – High-performance web application accelerator/reverse proxy and load balancer/HTTP router
• XAMPP – Package of web applications including Apache and MariaDB
• Zope – Web application server

Web search engines

• Searx – Self-hostable metasearch engine
• YaCy – P2P-based search engine

Other networking programs

• JXplorer – LDAP client
• Nextcloud – A fork of ownCloud
• OpenLDAP – LDAP server
• ownCloud – File share and sync server
• Wireshark – Network monitor

Office software

Text editors

Spreadsheet software

Office suites

• Apache OpenOffice – The cross platform office productivity suite from Apache Software Foundation (ASF) consists of programs for word processing, spreadsheets, presentation, diagrams and drawings, databases, etc.
• Calligra Suite – The office productivity suite from KDE consists of programs for word processing, spreadsheets, presentation, databases, vector graphics, and digital painting
• Collabora Online – Enterprise-ready edition of LibreOffice, web application, mobile phone, tablet, Chromebook and desktop (Windows, macOS, Linux)^[6]
• LibreOffice – The cross platform office productivity suite from The Document Foundation (TDF) consists of programs for word processing, spreadsheets, presentation, diagrams and drawings, databases, etc.
• OnlyOffice Desktop Editors – An open-source offline edition of the Cloud

Operating systems

Be advised that available distributions of these systems can contain, or offer to build and install, added software that is neither free software nor open-source.

• Linux: Debian, Slackware, among others.
• LineageOS: An android-based operative system for tablets and mobile phones.
• GNU Hurd

Emulation and Virtualization

• AppleWin
• DOSBox – DOS programs emulator (including PC games)
• GNOME Boxes
• Hercules (emulator)
• Kernel-based Virtual Machine
• QEMU
• VirtualBox – hosted hypervisor for x86 virtualization

Personal information managers

• Chandler – Developed by the Open Source Applications Foundation (OSAF)
• KAddressBook
• Kontact
• KOrganizer
• Mozilla Calendar – Mozilla-based, multi-platform calendar program
• Novell Evolution
• Perkeep – Personal data store for pictures
• Project.net – Commercial project management
• TeamLab – Platform for project management and collaboration

Programming language support

Bug trackers

• Bugzilla
• Mantis
• Mindquarry
• Redmine
• Trac

Code generators

• Bison
• CodeSynthesis XSD – XML Data Binding compiler for C++
• CodeSynthesis XSD/e – Validating XML parser/serializer and C++ XML Data Binding generator for mobile and embedded systems
• Flex lexical analyser – Generates lexical analyzers
• Open Scene Graph – 3D graphics application programming interface
• OpenSCDP – Open Smart Card Development Platform
• phpCodeGenie
• SableCC – Parser generator for Java and .NET
• SWIG – Simplified Wrapper and Interface Generator for several languages
• ^txt2regex$
• xmlbeansxx – XML Data Binding code generator for C++
• YAKINDU Statechart Tools – Statechart code generator for C++ and Java

Documentation generators

• Doxygen – Tool for writing software reference documentation. The documentation is written within code
• Mkd – Extracts software documentation from source code files, pseudocode, or comments
• Natural Docs – Claims to use a more natural language as input from the comments, hence its name

Configuration software

• Autoconf
• Automake
• BuildAMation
• CMake

Debuggers (for testing and trouble-shooting)

• GNU Debugger – A portable debugger that runs on many Unix-like systems
• Memtest86 – Stress-tests RAM on x86 machines
• Xnee – Record and replay tests

Integrated development environments

Version control systems

Reference management software

Risk Management

• Active Agenda – Operational risk management and Rapid application development platform

Science

Bioinformatics

Cheminformatics

• Chemistry Development Kit
• JOELib
• OpenBabel

Electronic lab notebooks

• Jupyter

Geographic information systems

Geoscience

Grid computing

• P-GRADE Portal – Grid portal software to create, execute, and monitor workflows through high-level Web interfaces

Microscope image processing

• CellProfiler – Automatic microscopic analysis, aimed at individuals lacking training in computer vision
• Endrov – Java-based plugin architecture designed to analyse complex spatio-temporal image data
• Fiji – ImageJ-based image processing
• Ilastik – Image-classification and segmentation software
• ImageJ – Image processing application developed at the National Institutes of Health
• IMOD – 2D and 3D analysis of electron microscopy data
• ITK – Development framework used for creation of image segmentation and registration programs
• KNIME – Data analytics, reporting, and integration platform
• VTK – C++ toolkit for 3D computer graphics, image processing, and visualisation
• 3DSlicer – Medical image analysis and visualisation

Molecular dynamics

• GROMACS – Protein, lipid, and nucleic acid simulation
• LAMMPS – Molecular dynamics software
• MDynaMix – General-purpose molecular dynamics, simulating mixtures of molecules
• ms2 – molecular dynamics and Monte Carlo simulation package to predict thermophysical properties of fluids
• NWChem – Quantum chemical and molecular dynamics software

Molecule viewer

• Avogadro – Plugin-extensible molecule visualisation
• BALLView – Molecular modeling and visualisation
• Jmol – 3D representation of molecules in many formats, for teaching use
• Molekel – Molecule viewing software
• MeshLab – Able to import PDB dataset and build up surfaces from them
• PyMOL – High-quality representations of small molecules and biological macromolecules
• QuteMol – Interactive molecule representations offering an array of innovative OpenGL visual effects
• RasMol – Visualizes biological macromolecules

Nanotechnology

• Ninithi – Visualise and analyse carbon allotropes, such as carbon nanotube, Fullerene, graphene nanoribbons

Plotting

• Veusz

Quantum chemistry

• CP2K – Atomistic and molecular simulation of solid-state, liquid, molecular, and biological systems

Screencast

• recordMyDesktop

Screensavers

• BOINC
• Electric Sheep
• XScreenSaver

Simulation software

• List of free and open source simulation software

Statistics

• R – Statistics software
• LimeSurvey – Online survey system

Theology

Bible study tools

• Go Bible – A free Bible viewer application for Java mobile phones
• Marcion – Coptic–English/Czech dictionary
• OpenLP – A worship presentation program licensed under the GNU General Public License
• The SWORD Project – The CrossWire Bible Society's free software project

Typesetting