Why Formulon

Formulon is for products that need spreadsheet calculation without embedding Excel. It gives you one C++17 engine and packages that same engine for WebAssembly, Python, native command-line workflows, direct native embedding, and AI agents through @libraz/formulon-mcp.

Core

One C++17 calculation engine

↓

Surfaces

@libraz/formulonWASM · browser & Node

packages/npm-nativeNative Node addon

formulon (PyPI)Python

CLIshell & CI

@libraz/formulon-mcpAI agents

The project optimizes for reproducible compatibility. The default behavior profile is win-365-ja_JP; goldens record observed Excel behavior, and accepted divergences are tracked explicitly instead of being hidden behind vague "Excel-like" claims.

What it solves

• Run .xlsx and .xlsb workbooks in services, jobs, and notebooks.
• Evaluate Excel formulas inside a browser or worker.
• Keep browser, Python, CLI, Native Node, and MCP results aligned because they share one core.
• Preserve workbook structure while recalculating values.
• Audit formula behavior against versioned oracle data.
• Let AI agents edit workbooks safely through @libraz/formulon-mcp.

What it does not try to solve

Formulon is not a spreadsheet UI, chart renderer, VBA runtime, PowerQuery/DAX engine, or legacy .xls implementation. Those boundaries keep the calculation engine small, testable, and embeddable.

Current status

Formulon is under active development and is not yet production-ready. The formula engine has broad local coverage and explicitly marks service-backed functions such as COPILOT, PY, and WEBSERVICE as unavailable service stubs rather than pretending to implement the corresponding Microsoft 365 services. APIs and package layout may still change before the first stable release. Validate business-critical workbooks with fixtures against the Excel profile you target.