Libre Calculator

LibreOffice is a free, open-source integrated office suite backed by The Document Foundation. It includes Writer, Calc, Impress, Draw, Math, and Base, and is compatible with most document formats and standards. The LibreOffice core repository is a read-only source mirror; contributions are directed through Gerrit. Its codebase includes shared modules for the system abstraction layer, widgets, rendering, document models, UNO APIs, and the Writer, Calc, Draw, and Impress applications.

opentax-engine is an open-source deterministic US tax calculator designed for AI agents and other applications. It accepts tax facts such as wages, filing status, and dependents, applies an encoded rule corpus, and returns cent-exact results with assumptions, legal citations, and a proof tree showing how each value was derived. If its rules cannot derive an answer, the project is designed to refuse rather than guess. The calculation can be selected for a date with an --as-of option, and the CLI accepts flags or JSON fact files; the videos also identify CLI, browser, and MCP integrations. The engine is implemented in TypeScript with no platform dependencies and can run in a self-contained browser HTML file containing the engine, rule corpus, and verifier. Proofs use canonical JSON, hashing, and a Merkle construction; the verifier independently re-derives the calculation and reports altered proof data, rule-corpus differences, or steps that do not match. The repository describes the project as AGPL-3.0 licensed, with commercial licenses available.

Aurelio is an open-source, self-hosted wealth-management and financial-planning app that runs on a user's computer and stores financial records locally. It tracks bank and brokerage cash, market-priced positions, costs, gains, dividends, fund holdings by country, sector, company, and currency, as well as recurring investments, homes, loans, cash flow, and savings goals. Its optional AI advisor uses OpenRouter and can answer questions from the user's records, search the web, and propose changes as cards that the user confirms or rejects. The app includes demo data, runs locally with Node.js and Python tooling, stores records in a local database with backups before format changes, and is licensed under the MIT License.

Expense Budget Tracker is a self-hosted, open-source personal-finance application for budgeting, tracking transactions and balances, transferring funds between accounts, and reporting across currencies. It runs on PostgreSQL and provides a web interface for managing budgets, transactions, accounts, and workspaces. The project includes a hosted MCP server and an Agent API. Compatible MCP clients can inspect workspace schemas, run restricted read queries, and, with the required write scope, execute approved data changes. The HTTP SQL API uses API keys and a flat table structure so AI agents can query and analyze financial data or import transactions from screenshots, CSV files, and PDF bank statements. The repository provides a Docker-based quick start that runs PostgreSQL, migrations, the web application, and a worker. The project is fully open source and designed for deployment on the user's own servers.

Univer is an open-source Office SDK from DreamNum for embedding spreadsheet, document, presentation, and structured-data experiences in web products and for processing workbooks and documents in Node.js. Its plugin-based architecture uses Canvas rendering, a formula engine, and a unified Facade API for workbooks, worksheets, ranges, formulas, documents, commands, and events; capabilities can be composed through presets or manually registered plugins, with support for React, Vue, and Web Components. The SDK provides browser and headless runtimes, server-oriented automation primitives, and AI-agent workflows for programmatically inspecting, editing, and verifying Office content. Open-source packages cover core spreadsheet and document editing, formulas, formatting, filtering, validation, comments, and related UI features; collaboration, advanced server features, and some import/export, chart, presentation, and enterprise capabilities are provided separately through Univer Pro. The repository is licensed under Apache-2.0.