IronCalc

IronCalc is an open-source web app that provides a spreadsheet engine and a set of tools for managing data in tabular formats. It is designed as a flexible backend that can be deployed as a self-hosted server via Docker or integrated directly into other software projects. The system functions as a core engine capable of handling complex calculations and file operations across different environments.

The software operates by separating the calculation logic from the presentation layer. While it currently includes a web-based preview for early testing, the project is designed to support multiple interface skins. This allows the engine to be used in a variety of contexts, including terminal based views, standalone desktop applications, or as a component within a custom web application. Users can deploy the environment quickly using Docker Compose to test the application in a browser.

Key features

• Support for reading and writing .xlsx files
• Implementation of over 300 spreadsheet functions
• Core engine written in Rust for performance
• Bindings for JavaScript and Python
• WebAssembly support for browser based execution
• Ability to create and manage multiple sheets within a model
• Support for cell formulas and cross-sheet references
• Deployment via Docker Compose

The architecture is built to be language agnostic, allowing the Rust core to be accessed via Python and JavaScript. This makes it suitable for developers who need to embed spreadsheet logic into a larger SaaS application without building a calculation engine from scratch. The API allows for programmatic control over the spreadsheet model, enabling users to set specific cell inputs, trigger evaluations of formulas, and save the final state to the local file system. It supports standard spreadsheet operations such as converting column numbers to letters and managing UTC time zones within the model.

IronCalc serves as a developer-centric spreadsheet infrastructure for those requiring a programmable, open-source calculation engine with a permissive MIT or Apache 2.0 license.