C# Business Software

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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.

  • Our Free Plans just got better! | Auth0 Icon
    Our Free Plans just got better! | Auth0

    With up to 25k MAUs and unlimited Okta connections, our Free Plan lets you focus on what you do best—building great apps.

    You asked, we delivered! Auth0 is excited to expand our Free and Paid plans to include more options so you can focus on building, deploying, and scaling applications without having to worry about your security. Auth0 now, thank yourself later.
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  • Automate contact and company data extraction Icon
    Automate contact and company data extraction

    Build lead generation pipelines that pull emails, phone numbers, and company details from directories, maps, social platforms. Full API access.

    Generate leads at scale without building or maintaining scrapers. Use 10,000+ ready-made tools that handle authentication, pagination, and anti-bot protection. Pull data from business directories, social profiles, and public sources, then export to your CRM or database via API. Schedule recurring extractions, enrich existing datasets, and integrate with your workflows.
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  • 1
    KeePass

    KeePass

    A lightweight and easy-to-use password manager

    KeePass Password Safe is a free, open source, lightweight, and easy-to-use password manager for Windows, Linux and Mac OS X, with ports for Android, iPhone/iPad and other mobile devices. With so many passwords to remember and the need to vary passwords to protect your valuable data, it’s nice to have KeePass to manage your passwords in a secure way. KeePass puts all your passwords in a highly encrypted database and locks them with one master key or a key file. As a result, you only have to remember one single master password or select the key file to unlock the whole database. And the databases are encrypted using the best and most secure encryption algorithms currently known, AES and Twofish. See our features page for details.
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    Downloads: 255,278 This Week
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  • 2
    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: 15,959 This Week
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  • 3
    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: 2,232 This Week
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  • 4
    Outlook CalDav Synchronizer

    Outlook CalDav Synchronizer

    Sync Outlook with Google, SOGo or any other CalDAV / CardDAV server

    Free Outlook Plugin, which synchronizes events, tasks and contacts between Outlook and Google, SOGo, NextCloud, Horde or any other CalDAV or CardDAV server. Supported Outlook versions are 2021, 2019, 2016, 2013, 2010 and 2007 and Office 365 for Desktop. This project was initially developed as a master thesis project at the University of Applied Sciences Technikum Wien, Software Engineering Degree program. Outlook CalDav Synchronizer is Free and Open-Source Software (FOSS), still you can support the project by donating on Sourceforge or directly within the About dialog of our Plugin. Contact us for enterprise support at https://caldavsynchronizer.org/enterprise/contact
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    Downloads: 701 This Week
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  • Turn more customers into advocates. Icon
    Turn more customers into advocates.

    Fight skyrocketing paid media costs by turning your customers into a primary vehicle for acquisition, awareness, and activation with Extole.

    The platform's advanced capabilities ensure companies get the most out of their referral programs. Leverage custom events, profiles, and attributes to enable dynamic, audience-specific referral experiences. Use first-party data to tailor customer segment messaging, rewards, and engagement strategies. Use our flexible APIs to build management capabilities and consumer experiences–headlessly or hybrid. We have all the tools you need to build scalable, secure, and high-performing referral programs.
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  • 5
    Windows Calculator

    Windows Calculator

    A simple yet powerful calculator that ships with Windows

    Calculator is the open source version of the Microsoft Windows Calculator application. It is a modern Windows app written in C++ and C#, offering standard, scientific, and programmer modes, unit/currency conversion, date calculations, and history/memory operations. It ships preinstalled with Windows and is actively developed on GitHub. Standard Calculator functionality, which offers basic operations and evaluates commands immediately as they are entered. Scientific Calculator functionality, which offers expanded operations and evaluates commands using the order of operations. Programmer Calculator functionality, which offers common mathematical operations for developers, including conversion between common bases.
    Downloads: 118 This Week
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  • 6
    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: 307 This Week
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  • 7
    FModel

    FModel

    Unreal Engine Archives Explorer

    FModel is a freeware application designed to explore Unreal Engine games archives, allowing users to delve into the assets and structures of games developed with Unreal Engine.
    Downloads: 62 This Week
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  • 8
    PDFCreator

    PDFCreator

    Converts every printable document to PDF, JPG, PNG, TIF and more

    PDFCreator creates professional PDFs with just a few clicks and it's free. PDFCreator comes with many professional features to merge documents, send emails, and more. PDFCreator easily creates PDFs from any Windows program. Use it like a printer in Word, Excel, or any other Windows application. A PDF takes less storage space, and is easier to send with email. Make PDF creator part of your the software suite you have installed on your computer for easy PDF creation. PDFCreator also comes with a COM programming interface that allows to integrate PDFCreator in other applications and a server mode to share PDFCreator on a network.
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    Downloads: 852 This Week
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  • 9
    PDFPatcher

    PDFPatcher

    A versatile toolkit for PDF manipulation

    PDFPatcher (aka “PDF补丁丁”) is a versatile toolkit for PDF manipulation—editing document metadata, bookmarks, page layout, content restrictions, rotation, compression, merging/splitting, image extraction, and more, all within an intuitive interface. Merge/split PDFs or images, preserve or add bookmarks, and set page dimensions. Batch style/color/target changes, regex/XPath search/replace, mid‑page positioning. Modify PDF metadata, page numbers, links, initial view mode, and remove open actions.
    Downloads: 28 This Week
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  • eProcurement Software Icon
    eProcurement Software

    Enterprises and companies seeking a solution to manage all their procurement operations and processes

    eBuyerAssist by Eyvo is a cloud-based procurement solution designed for businesses of all sizes and industries. Fully modular and scalable, it streamlines the entire procurement lifecycle—from requisition to fulfillment. The platform includes powerful tools for strategic sourcing, supplier management, warehouse operations, and contract oversight. Additional modules cover purchase orders, approval workflows, inventory and asset management, customer orders, budget control, cost accounting, invoice matching, vendor credit checks, and risk analysis. eBuyerAssist centralizes all procurement functions into a single, easy-to-use system—improving visibility, control, and efficiency across your organization. Whether you're aiming to reduce costs, enhance compliance, or align procurement with broader business goals, eBuyerAssist helps you get there faster, smarter, and with measurable results.
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  • 10

    Mpp Viewer

    MPP Viewer is a viewer for Microsoft Project files

    MPP Viewer is a simple viewer for Microsoft Project files. It allows you to Open, Export to excel, Print mpp files. It works well with Project 2016 / 2007 / 2003 / 2000 files. Allows hierarchical view of tasks, resources view and more. MPP Viewer 4.0 Beta 1. Support for viewing Notes 2. Addition of resources column in excel export 3. Addition of % complete column in resources view 4. Upgrade of MPXJ library to use v5.9 5. Bug fixes MPP Viewer 3.0 - New features include 1. Support for viewing custom columns 2. Preview of notes 3. Project properties MPP Viewer 2.0 is more stable version and works well with most of the files 1.0 was not able to work with. NOTE: 1. MPP Viewer 4.0 needs .Net framework 4.6.2 to run. 2. If you are running Windows XP, Please use MPP Viewer 1.0. Since .Net 4.5 is not available for Windows XP
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    Downloads: 140 This Week
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  • 11
    JExcelApi is a java library which provides the ability to read, write, and modify Microsoft Excel spreadsheets. This project mirrors the files on http://www.jexcelapi.org, which has been known to go down on occasion.
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    Downloads: 124 This Week
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  • 12
    Outlook Google Calendar Sync

    Outlook Google Calendar Sync

    Sync your Outlook and Google calendars

    Offers calendar synchronization between Outlook and Google, including attendees and reminders. Completely free, no install necessary, works behind web proxies and actively developed. Supports all versions of Outlook from 2003 to 2019/Microsoft365 64-bit! Installable and portable options - even runs from a USB thumbdrive. Synchronises items in any calendar folder, including those shared with you. Differential comparison updates only attributes that have changed. Customizable date range to synchronize, past and future. Frequency of automatic syncs, including push-sync from Outlook. Configurable proxy settings, or use Internet Explorer's. Merge new events into existing on the destination calendar. Prompt on deletion of items. Ability to obfuscate custom words for privacy/security. Option to force items as public or private in target calendar. Syncs recurring items properly as a series.
    Downloads: 18 This Week
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  • 13
    The goal for this project is to provide translators to allow for interoperability between applications based on ODF (OpenDocument) 1.1 standards and ECMA Office OpenXML based Office applications.
    Downloads: 66 This Week
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  • 14
    PDFsharp

    PDFsharp

    PDFsharp is a .NET library for creating and modifying PDF documents.

    PDFsharp moved to https://github.com/empira/PDFsharp PDFsharp is a .NET library for creating and modifying Adobe PDF documents programmatically from any .NET language like C# or VB.NET. PDFsharp defines classes for the objects found in PDF files, so you never have to deal with IDs or references directly. The downloads include MigraDoc Foundation, a .NET library for creating documents on the fly (supports PDF and RTF). PDFsharp is the .NET library that easily creates and processes PDF documents on the fly from any .NET language. The same drawing routines can be used to create PDF documents, draw on the screen, or send output to any printer. MigraDoc Foundation is the .NET library that easily creates documents based on an object model with paragraphs, tables, styles, etc. and renders them into PDF, XPS, or RTF.
    Downloads: 58 This Week
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  • 15
    CSV Lint

    CSV Lint

    CSV Lint plug-in for Notepad++ for syntax highlighting

    CSV Lint plug-in for Notepad++ for syntax highlighting, csv validation, automatic column and datatype detecting fixed width datasets, change datetime format, decimal separator, sort data, count unique values, convert to xml, json, sql etc. A plugin for data cleaning and working with messy data files. Use CSV Lint for metadata discovery, technical data validation, and reformatting on tabular data files. It is not meant to be a replacement for spreadsheet programs like Excel or SPSS, but rather it's a quality control tool to examine, verify or polish up a dataset before further processing.
    Downloads: 12 This Week
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  • 16
    NASA World Wind is a graphically rich 3D virtual globe for use on desktop computers running Windows. It combines NASA imagery generated from satellites that have produced Blue Marble, Landsat 7, SRTM, MODIS and more.
    Downloads: 57 This Week
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  • 17
    An easy, simple tool for merging PDF files.
    Downloads: 78 This Week
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  • 18
    ZedGraph is a class library, user control, and web control for .net, written in C#, for drawing 2D Line, Bar, and Pie Charts. It features full, detailed customization capabilities, but most options have defaults for ease of use.
    Downloads: 48 This Week
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  • 19
    Windows X App Remover

    Windows X App Remover

    Remove Modern UI Apps from Windows Installations or Images

    Remove Modern UI (Metro) Apps from Windows. With the Windows X App Remover, you can easily read out which Apps are installed and remove the ones you do not want anymore. -News, 14rd December 2015- Version 1.02 is out. Some Apps can't be removed, because Microsoft does not allow it ("System Apps"). This is now correctly handled by the program. If you encounter any bugs or you miss anything, feel free to contact me!
    Downloads: 75 This Week
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  • 20
    OpenSCAD Graph Editor

    OpenSCAD Graph Editor

    OpenSCAD Graph Editor

    OpenSCAD Graph Editor is a graphical user interface for OpenSCAD that allows you to create 3D models by connecting nodes in a graph. The editor will automatically generate OpenSCAD code for you. It integrates with the OpenSCAD program so you can preview your models in real-time while you are editing the graph. Please check the manual to find out how to install and use the program.
    Downloads: 9 This Week
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  • 21
    nopCommerce

    nopCommerce

    The most popular open-source eCommerce shopping cart solution

    nopCommerce is the best open-source eCommerce shopping cart solution. nopCommerce is free, and it is the most popular ASP.NET eCommerce platform. The product is being developed and supported by the professional team since 2008. nopCommerce has been downloaded more than 3,000,000 times. The active developer community has more than 250,000 members. nopCommerce runs on ASP.NET Core 5 with an MS SQL 2012 (or higher) backend database. nopCommerce is cross-platform, and you can run it on Windows, Linux, or Mac. nopCommerce supports Docker and MySQL out of the box, so you can easily run nopCommerce on a Linux machine. nopCommerce supports PostgreSQL database. nopCommerce fully supports web farms. You can read more about it here. All methods in nopCommerce are async. nopCommerce supports multi-factor authentication out of the box.
    Downloads: 8 This Week
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  • 22
    Tadween is a powerful multilingual application allowing users to write Arabic in applications that support Unicode but don't fully support Arabic.
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    Downloads: 55 This Week
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  • 23

    Pdf Split and Merge with Bookmark Import

    PDF merging with bookmarks and pagination

    PDF Split and Merge tool is implemented using the PdfSharp library and is either GUI or command driven.It is useful for automated document creation.It allows bookmarks from the input pdfs to be imported and flexibly embedded in the destination document. PDF pages can be numbered and annotated with a footer label.
    Downloads: 34 This Week
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  • 24
    DinkToPdf

    DinkToPdf

    C# .NET Core wrapper for wkhtmltopdf library that uses Webkit engine

    .NET Core P/Invoke wrapper for wkhtmltopdf library that uses Webkit engine to convert HTML pages to PDF. Copy the native library to root folder of your project. From there .NET Core loads the native library when the native method is called with P/Invoke. You can find the latest version of the native library. Select the appropriate library for your OS and platform (64 or 32-bit). The library was not tested with IIS. The library was tested in console applications and with Kestrel web server both for Web Applications and Web API.
    Downloads: 7 This Week
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  • 25
    OSHMI - Open Substation HMI

    OSHMI - Open Substation HMI

    SCADA HMI for substations, IoT and automation applications

    Now with IEC61850 support! This project combines existing open source projects and tools to create a very capable, mobile and cloud-friendly HMI system that can rival proprietary software. This approach makes it possible to join forces of each project (Chromium, SVG/HTML5, PHP, Lua, SQLite, Inkscape, Lib61850, OpenDNP3, Nginx, Vega, PostgreSQL, Grafana,…) to achieve a great set of open, evergreen, modular and customizable tools for building great HMIs for automation projects. This is not a toy project! It's been actually used in dozens of substations up to 230kV level and also in control centers with configurations up to 70.000 tags. Feel free to ask questions in the "Discussion" section. Help sponsoring OSHMI here https://github.com/sponsors/riclolsen. >>> Have a look also at my new SCADA project here: https://github.com/riclolsen/json-scada
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    Downloads: 47 This Week
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