Headless Spreadsheet Engine

Formulon

Name: Formulon
Author: libraz

A workbook calculation platform for apps, automation, and AI agents.

Formulon ships one C++17 calculation core across WASM, Python, Native Node, CLI, and MCP so applications can read, evaluate, recalculate, and write .xlsx / .xlsb files without Excel, Microsoft runtimes, or COM automation.

Quick Start Use from MCP Browse scenarios Try the live demos

v0.12.0: Documentation target
508 / 523: Local / recognized functions
43: MCP tools

The remaining 15 require external services such as Copilot, cloud Python, image fetch, market data, or CUBE connections. See why

Agent interface

Let AI agents work inside real workbooks.

formulon-mcp exposes the Formulon calculation core as MCP tools. Agents can open .xlsx or .xlsb files, inspect structure, edit cells and sheets, recalculate, and save the result.

Set up MCP GitHub

Codex config@libraz/formulon-mcp

[mcp_servers.formulon]
command = "npx"
args = ["-y", "@libraz/formulon-mcp"]

Formulaeval, lookup, trace

Workbookopen, inspect, recalc, save

Editcells, sheets, names, ranges

Layoutmerges, comments, validation

Ecosystem

How the packages relate

L1 is the C++17 calculation core (formulon). L2 provides the WASM, Python, Native Node, and CLI interfaces. L3 contains packages for applications and agents. L4 is the consumer.

L4Consumer

AI agentsClaude Code · Codex · Claude Desktop

Browser appsReact / Vue / vanilla frontends

L3App-facing package

@libraz/formulon-mcpstdio MCP server · 43 tools @libraz/formulon-cellframework-free spreadsheet UI host

@libraz/formulon-cell-react
@libraz/formulon-cell-vue

L2Language interface

@libraz/formulonnpm · WASM binding for browser and Node formulonPyPI · Python scripts and batch jobs formulon (CLI)GitHub Releases binary · CI and shell Native NodeSource-built Node.js native addon

L1Calculation core

formulonC++17 calculation core · Excel-derived oracle data (github.com/libraz/formulon)

Operations

Start from the job.

Formulon is easiest to evaluate from the place where the workbook runs. Pick the deployment first, then move into the runtime, API, and compatibility details that matter for that path.

DeskUpload workbook in a browserWASM loads workbook files, edits formulas, and recalculates in the browser without an Office runtime.BackendRecalculate inside a Node serviceAccept .xlsx files in an upload API or internal service, then recalculate with Native Node or WASM.BatchBatch recalculation from PythonRecalculate workbooks in report generation, ETL pipelines, and scheduled jobs.PipelineWorkbook regression in CIDetect calculation changes by comparing checked-in formula and value snapshots.AgentEdit workbooks from an AI agentUse MCP tools to open .xlsx or .xlsb files, mutate cells, sheets, names, and layout, then recalculate.

MCPWorkbook operation tools for AI agents RuntimeWASM, Python, Native Node, and CLI share one C++17 core Use casesBrowser upload, Python batch, and CI workbook regression WorkbookDynamic arrays, PivotTables, structural edits, iterative calculation CompatibilityFunction availability and Excel oracle data

Live Workbook

Try functions through npm formulon

This sheet is the real formulon-cell surface backed by @libraz/formulon. Pick a function to rewrite F2 and recalculate it in the WASM engine. Array functions spill their result down column F.

formulon-cell documentation Open full demo How spilling works

Spreadsheet UI: formulon-cell