Browse free open source C Business Software and projects below. Use the toggles on the left to filter open source C Business Software by OS, license, language, programming language, and project status.

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  • 1
    TurboVNC

    TurboVNC

    High-speed, 3D-friendly, TightVNC-compatible remote desktop software

    TurboVNC is a high-performance, enterprise-quality version of VNC based on TightVNC, TigerVNC, and X.org. It contains a variant of Tight encoding that is tuned for maximum performance and compression with 3D applications (VirtualGL), video, and other image-intensive workloads. TurboVNC, in combination with VirtualGL, provides a complete solution for remotely displaying 3D applications with interactive performance. TurboVNC's high-speed encoding methods have been adopted by TigerVNC and libvncserver, and TurboVNC is also compatible with any other TightVNC derivative. TurboVNC forked from TightVNC in 2004 and still covers all of the TightVNC 1.3.x features, but TurboVNC contains numerous feature enhancements and bug fixes relative to TightVNC, and it compresses 3D and video workloads much better than TightVNC while using generally only 5-20% of the CPU time of the latter. Using non-default settings, TurboVNC can also be made to compress 2D workloads as "tightly" as TightVNC.
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    Downloads: 130,043 This Week
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  • 2
    VirtualGL

    VirtualGL

    3D Without Boundaries

    VirtualGL redirects 3D commands from a Unix/Linux OpenGL application onto a server-side GPU and converts the rendered 3D images into a video stream with which remote clients can interact to view and control the 3D application in real time.
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    Downloads: 72,856 This Week
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  • 3
    GnuWin

    GnuWin

    Provides native Win32 open source ports and utilities

    GnuWin provides Win32-versions of GNU tools, or tools with a similar open source licence. The ports are native ports, relying only on libraries provided with any modern 32-bits MS-Windows operating system, such as 2000 / XP / Vista / 7
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    Downloads: 41,972 This Week
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  • 4
    Technical analysis library with indicators like ADX, MACD, RSI, Stochastic, TRIX... includes also candlestick pattern recognition. Useful for trading application developpers using either Excel, .NET, Mono, Java, Perl or C/C++.
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    Downloads: 12,143 This Week
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  • AI-generated apps that pass security review Icon
    AI-generated apps that pass security review

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    Retool lets you generate dashboards, admin panels, and workflows directly on your data. Type something like “Build me a revenue dashboard on my Stripe data” and get a working app with security, permissions, and compliance built in from day one. Whether on our cloud or self-hosted, create the internal software your team needs without compromising enterprise standards or control.
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  • 5
    GnuCash

    GnuCash

    Personal and small-business finance manager

    GnuCash is a personal and small-business finance manager with a check-book like register GUI to enter and track bank accounts, stocks, income and expenses. GnuCash is designed to be simple and easy to use but still based on formal accounting principles.
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    Downloads: 8,313 This Week
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  • 6
    gnuplot

    gnuplot

    A portable, multi-platform, command-line driven graphing utility

    A famous scientific plotting package, features include 2D and 3D plotting, a huge number of output formats, interactive input or script-driven options, and a large set of scripted examples.
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    Downloads: 4,822 This Week
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  • 7
    Zint Barcode Generator

    Zint Barcode Generator

    A barcode encoding library supporting over 50 symbologies.

    Encodes data into any of the following: Australia Post, Aztec Code & Runes, BC412, Channel, Codabar, Codablock-F, Code 11, Code 128, Code 16K, Code 2 of 5 (incl. IATA, Interleaved, Data Logic, ITF-14, Deutsche Post Leitcode & Identcode), Code 32 (Italian Pharmacode), Code 39, Code 39+, Code 49, Code 93, Code One, DAFT, Data Matrix (incl. DMRE), DotCode, DPD, Dutch Post KIX, EAN, FIM, Flattermarken, Grid Matrix, GS1 DataBar (incl. stacked & GS1 Composite symbols), GS1-128, Han Xin, HIBC, ISBN, Japan Post, Korea Post, LOGMARS, MaxiCode, NVE-18 ( SSCC-18), PDF417 & MicroPDF417, Pharmacode, PLANET, POSTNET, Plessey (MSI & UK), PZN, QR Code, Micro QR & rMQR, Royal Mail RM4SCC & Mailmark, Telepen, Ultracode, UPC-A, UPC-E, UPNQR, UPU S10, USPS Intelligent Mail and VIN. Automated ECI switching to support all Unicode characters and automated FNC1 character insertion in GS1 mode. Save to BMP, EMF, EPS, GIF, PCX, PNG, SVG and TIF. Includes CLI, GUI and API for calling from other applications.
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    Downloads: 2,871 This Week
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  • 8
    Maxima -- GPL CAS based on DOE-MACSYMA

    Maxima -- GPL CAS based on DOE-MACSYMA

    Computer Algebra System written in Common Lisp

    Maxima is a computer algebra system comparable to commercial systems like Mathematica and Maple. It emphasizes symbolic mathematical computation: algebra, trigonometry, calculus, and much more. For example, Maxima solves x^2-r*x-s^2-r*s=0, giving the symbolic results [x=r+s, x=-s]. It can also calculate with exact integers and fractions, native floating-point, and high-precision big floats. Maxima has user-friendly front-ends, an online manual, plotting commands, and numerical libraries. It features its own programming language, and many users have contributed useful packages in various areas over the decades. It is GPL-licensed and largely written in Common Lisp. Executables can be downloaded for Windows, Mac, Linux, and Android; source code is also available. An active community maintains and extends the system. Website: https://maxima.sourceforge.io Additional add-on packages for Maxima can be found at: https://github.com/maxima-project-on-github/maxima-packages
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    Downloads: 2,429 This Week
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  • 9
    FreeImage is a library project for developers who would like to support popular graphics image formats (PNG, JPEG, TIFF, BMP and others). Some highlights are: extremely simple in use, not limited to the local PC (unique FreeImageIO) and Plugin driven!
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    Downloads: 2,208 This Week
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  • 10
    Pandora Open

    Pandora Open

    Open Source Monitoring System for performance and availability.

    Pandora OPEN is a high-performance, 100% open-source monitoring ecosystem, born as the independent evolution of the Pandora FMS community branch after version 777. Licensed under GPLv2, it provides a modular and sovereign platform for supervising networks, servers, and applications without commercial dependencies. It features multi-platform agents, remote monitoring (SNMP, WMI, HTTP), GIS maps, and advanced visual dashboards. Entirely maintained by the community on GitHub, it ensures total transparency, technical flexibility, and absolute freedom for system administrators.
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    Downloads: 1,547 This Week
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  • 11
    Gwyddion

    Gwyddion

    Scanning probe microscopy data visualisation and analysis

    A data visualization and processing tool for scanning probe microscopy (SPM, i.e. AFM, STM, MFM, SNOM/NSOM, ...) and profilometry data, useful also for general image and 2D data analysis.
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    Downloads: 1,404 This Week
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  • 12
    A comprehensive software suite for reading barcodes. Supports EAN/UPC, Code 128, Code 39, Interleaved 2 of 5 and QR Code. Includes libraries and applications for decoding captured barcode images and using a video device (eg, webcam) as a barcode scanner.
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    Downloads: 912 This Week
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  • 13
    SumatraPDF Reader

    SumatraPDF Reader

    Multi-format (PDF, EPUB, MOBI, FB2, CHM, XPS, DjVu) reader for Windows

    Sumatra PDF is a free PDF, eBook (ePub, Mobi), XPS, DjVu, CHM, Comic Book (CBZ and CBR) viewer for Windows. Sumatra PDF is powerful, small, portable and starts up very fast. Simplicity of the user interface has a high priority. Portable version is a single executable, can be run from USB drive and doesn't write to registry. For best results use the latest release available as that's what I use and test with. If things don't compile, first make sure you're using the latest version of Visual Studio. To compile you need Visual Studio 2019 16.6 or later. Free Community edition works.
    Downloads: 89 This Week
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  • 14
    Grisbi
    Grisbi is a very functional personal financial management program with a reasonable set of homefinance features.
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    Downloads: 454 This Week
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  • 15
    XTrkCAD Model RR Track Planner

    XTrkCAD Model RR Track Planner

    Model Railway CAD program

    XTrackCAD is a open-source, free, CAD program for designing model railroad layouts. You can easily create layout of any scale or size. Libraries for many brands, scales and gauges of track and turnouts/points and model structures are included. Adding new components is easy with the built-in editor. It runs on Windows, Mac and Linux,
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    Downloads: 414 This Week
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  • 16
    FreeMat
    Freemat is an interpreted, matrix-oriented development environment for engineering and scientific applications, similar to the commercial package MATLAB. Freemat provides visualization, image manipulation, and plotting as well as parallel programming.
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    Downloads: 296 This Week
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  • 17
    Nagios Open Source

    Nagios Open Source

    Nagios Open Source network monitoring software - The Standard In ITM

    Nagios network monitoring software is a powerful, enterprise-class host, server, application, and network monitoring tools. Designed to be fast, flexible, and rock-solid stable. Nagios runs on *NIX hosts and can monitor Windows, Linux/Unix/BSD, Netware, and network devices.
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    Downloads: 288 This Week
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  • 18
    Luminance HDR

    Luminance HDR

    Complete solution for HDR photography

    Luminance HDR is a complete suite for HDR imaging workflow. It provides a wide range of functionalities, during both the fusion stage and the tonemapping stage. Its graphical user interface, based on Qt5, runs on a variety of platforms, such as Microsoft Windows, Mac OS X 10.9 and later and several Unix flavors (Linux, FreeBSD and others). Input images can be supplied in multiple formats, from JPEG to RAW files. In the same way, output can be saved in many different formats as well, from JPEG to TIFF (both 8 bit and 16 bit per channel), enabling all the power of your post processing tools.
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    Downloads: 323 This Week
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  • 19
    Open Tax Solver

    Open Tax Solver

    Calculates income tax form entries, helps do your taxes.

    OTS is a safe, secure, easy-to-use program for calculating Tax Return Form entries, and determining your tax-owed or refund-due, for Federal or State personal income taxes. Includes updated versions for US 1040, Schedules A, B, C, D, and for several states. OTS provides both graphical and textual interfaces for quickly filing out your tax forms. --- Best way to download the correct version for your platform -- go to the OTS WEBSITE: =====> https://opentaxsolver.sourceforge.net/
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    Downloads: 358 This Week
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  • 20
    Viking GPS data editor and analyzer

    Viking GPS data editor and analyzer

    Viking is a free/open source program to manage GPS data

    Viking is a free/open source program to manage GPS data. You can import, plot and create tracks, routes and waypoints, show OSM, Bing Aerial and other maps, geotag images, create routes using OSRM, see real-time GPS position (not in Windows), make maps using Mapnik (not in Windows), control items, etc. It is written in mostly in C (with some C++) & the GTK+3 toolkit. Viking is currently dual managed - with a corresponding Github presence at: https://github.com/viking-gps/viking Where you may find it easier to view the code and raise issues there too.
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    Downloads: 261 This Week
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  • 21

    TILP - TI Linking Program

    TI graphing calculators <-> computer communication software

    TILP (formerly GtkTiLink) can transfer data between Texas Instruments graphing calculators and a computer. It works with all link cables (parallel, serial, Black/Gray/Silver/Direct Link) and it supports the TI-Z80 series (73..86), the TI-eZ80 series (83PCE, 84+CE), the TI-68k series (89, 92, 92+, V200, 89T) and the Nspire series (Nspire Clickpad / Touchpad / CX, both CAS and non-CAS). The project is now managed on Github, https://github.com/debrouxl/tilp_and_gfm . It uses the libti* libraries, https://github.com/debrouxl/tilibs . Install script for *nix: https://github.com/debrouxl/tilp_and_gfm/blob/master/tilp/trunk/build/scripts/install_tilp.sh
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    Downloads: 328 This Week
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  • 22
    PNotes
    PNotes is light-weight, flexible, skinnable manager of virtual notes on your desktop. It supports multiple languages, individual note's settings, transparency and scheduling. Absolutely portable as well - no traces in registry. PNotes.NET edition requires .NET framework 4 Client Profile
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    Downloads: 217 This Week
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  • 23
    Elmer finite element software

    Elmer finite element software

    Open source finite element software for multiphysical problems

    Elmer is a finite element software for numerical solution of partial differential equations and multiphysical problems. It includes models of structural mechanics, fluid dynamics, heat transfer, electromagnetics etc. Elmer home is www.csc.fi/elmer
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    Downloads: 234 This Week
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  • 24
    Amide's a Medical Image Data Examiner: Amide is a tool for viewing, registering, and analyzing anatomical and functional volumetric medical imaging data sets.
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    Downloads: 182 This Week
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  • 25
    Grafana

    Grafana

    Leading open-source visualization and observability platform

    Grafana OSS is the leading open-source platform for visualization and observability. It enables teams to query, visualize, alert on, and explore telemetry data from multiple sources in a single interface. With support for 100+ data source plugins—including Prometheus, Loki, Elasticsearch, InfluxDB, SQL/NoSQL databases, and OpenTelemetry—Grafana helps teams correlate metrics, logs, and traces across applications and infrastructure. Users can build interactive dashboards with rich visualizations, template variables, and reusable panels to monitor systems and troubleshoot issues in real time. Grafana includes capabilities such as ad hoc data exploration, alerting, annotations, and flexible query support. Its extensible plugin ecosystem integrates with cloud platforms, databases, and developer tools—allowing teams to build observability workflows without vendor lock-in. The easiest way to get started with Grafana is with Grafana Cloud, our fully managed, full-stack observability platform.
    Downloads: 29 This Week
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