Open Source C Financial Software

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.

Technical analysis library with indicators like ADX, MACD, RSI, Stochastic and TRIX, plus candlestick pattern recognition. Docs: https://ta-lib.org Available natively in C/C++, Java, Rust and C# with wrappers for python, R and many other ecosystems. MOVED TO GITHUB: https://github.com/TA-Lib/ta-lib . No further support is provided on SourceForge. Release 0.4.0 is very outdated, please check github for the most recent release.

Grisbi is a very functional personal financial management program with a reasonable set of homefinance features.

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/

esniper was a lightweight console application for sniping eBay auctions. *It does not work anymore.* The development stopped in 2020 because ebay has changed the login mechanism in a way we could not handle in the existing code.

XonGrid is a free Excel library of functions to perform 1D, 2D, 3D, 4D and arbitrary dimension (ND) interpolations from scattered data.

This is a C library to check the validity of German and Austrian Bank Account Numbers. All currently defined test methods by Deutsche Bundesbank (Dec 2017: 00 to E4) are implemented. Modules for AWK, Perl, PHP, Python, Ruby, C#.net and VB.net are included too. The package includes also an IBAN converter to generate (german) IBANs and BICs from account data. All currently defined IBAN rules by Deutsche Bundesbank are implemented (Dec 2017: 57 rules) and tested against independent solutions.

A multiplatform C++ library for dynamic generation of Excel .xls files containing multiple worksheets. Unlike .csv files, these can be directly opened by Excel and thus provide an excellent way to output large data sets that require further analysis. To see the latest changes, select "Files" and view the README text displayed at the bottom of that pane. IMPORTANT: Major changes are contained in the current SVN source. If you have time please try to use it or the xlslib-package-2.4.0b1.zip archive, and enter bug reports on any problems! Changes: - library specific strings now in their own namespace - iOS Objective-C library - most project files updated (MSVS etc) - C bridge now supports formulas Note: there is a related SF project, libxls, to read Excel files.

Port of GRISBI a GPL accounting manager (http://www.grisbi.org/) under Windows. Depending of the GRISBI version the port should be done using CYGWIN or in a native way. You will found here all stuff needed to install, use and compile GRISBI under Windows

A real-time financial derivatives calculator supporting 171+ models from QuantLib, Financial Numerical Recipes in C++ and MetaOptions. Matrices of prices are created with iterating strikes and/or months. A strike control system can produce any strike. A generalized date engine can calculate re-occuring distances to any industry used expiration into the future. Spread engine with spread views. Models Supported: Black-Scholes, Merton-73, Black-76, Roll Geske Whaley, Garman KohlHagen, Jump Diffusion, Quanto, Vasicek Bond Option, Turnbull Wakeman Asian, TimeSwitchOption, Look Barrier, Bachelier, PartialTimeBarrier, GapOption, Extreme Spread Option, Simple Chooser, ComplexChooser, PartialFixedLB, Executive, CashOrNothing, Extendible Writer, OptionsOnOptions, BAWAmericanApprox, BSAmericanApprox, AssetOrNothing, Bisection, BAWbisection, BSbisection, Gfrench, Gcarry, Swapoption, Complex Chooser, Super Share, EquityLinkedFXO, Spread Approximation, BinaryBarrier and more

Trading Desk Pro is a desktop application for viewing market charts and practicing advanced trades with virtual funds. It supports cryptocurrencies. The app includes candlestick charts, technical indicators, simulated srders, AI-assisted chart analysis and a trade journal. Also, users can review their simulated trades and account performance, with records stored locally. The interface supports multiple languages! Lastly, if you want to delete this app, please download 'TradingDeskPro_remove.bat'. (As I am Korean, I am not fluent in English, so I wrote most of the explanation with the help of AI. I ask for your understanding!) *THIS CONTENT IS STRICTLY COPYRIGHTED, AND ILLEGAL DISTRIBUTION MAY RESULT IN LEGAL ACTION. IF YOU WANT TO SHARE THIS APP, PLEASE ENSURE YOU INCLUDE THE NAME OF THIS WEBSITE*

«HomeBank» is the software you have always wanted to manage your personal accounts. It brings you many features to analyze your finances in a detailed way instantly and dynamically with powerfull report tools based on filtering and graphical charts.

This is the LibOFX library. It is a parser and an API designed to allow applications to support the OFX banking standard (mostly used for bank statement download). To my knowledge, it is the first working OpenSource implementation on the client side.

A library to generate the bidimensional barcode PDF417. The generated result is a byte array representing the barcode image that can be included in the users application.

Utility to validate, extract, show and create digital documents included in files with "pk7" and "fp7" extensions such as electronic bills provided by some phone companies in Spain like Movistar and Telefonica.

GnoTime (formerly GTT, the Gnome Time Tracker) is a desktop utility for tracking the amount of time spent on projects, keeping a to-do list, maintaining a diary, and generating reports and invoices based on that time.

Read data from Excel 97+ spread sheets without Microsoft! Provides an API to write applications that read Excel documents. The xlreader tool converts data to tab delimited, CSV or SQL inserts. Written in C. Based on the the Java version by Andrew Khan.

A library to check bank account numbers and bank codes (BLZ) of German Banks. It is based on the specifications of the "Deutsche Bundesbank".

muhasebeci is a free accounting program. it is for all size firms.

💰 BudgetBuddy is a modern, intelligent personal finance app built with Flutter to help you take full control of your money. 📊 Track daily expenses, monitor financial goals, and manage installments — all backed by an 🤖 AI Financial Advisor powered by OpenRouter that gives real-time advice on whether a purchase fits your budget. 💳 View your Net Worth, Bank Total, and Cash Reserves through beautifully designed glassmorphic swipeable cards. 🔒 Your data stays secure with biometric fingerprint and face unlock, and you can ☁️ back it all up safely to Google Drive. 🌍 Built for local users too — BudgetBuddy is fully bilingual (English & Sinhala), supports 🌗 dark/light mode, and can 📱 automatically read and categorize SMS bank transaction alerts so you never have to log expenses manually. Whether you are tracking petty cash, recurring bills, or long-term savings goals — BudgetBuddy makes personal finance simple, secure, and smart. ✨

Since version 1.3.0beta AqBanking includes all code and modules of AqHBCI. So please visit http://www.aquamaniac.de/aqbanking/.

Designed especially for restaurants. Focus on using cheap standard PC components, aside from POS printer. Multiple waiters/bills/screens at the same time possible. GUI design tested/optimized on real waiters (at a restaurant in Harz Mountains / Germany).

OpenHBCI is an Open Source library implementing the German homebanking standard HBCI, to be used in C++ or C.

GkrellStock monitors stock quotes for given Tickers from various markets (USA, Europe, Canada, Asia, Australia).

gBilling is a Internet Cafe Billing System consists of Server and Client, gBilling is especially made in Indonesian Language, run in Linux and Windows, written in C and GTK2.