The document API for files your customers already have

Update spreadsheets, fill PDF forms and compare Word documents from your code. Formatting and formulas stay the way they were.

Try it Read the docs

Review before you send

See the original and the updated file side by side, with every change highlighted. Hold the files you choose until someone on your team approves them.

Side-by-side view. Changed cells and paragraphs are highlighted.
Approvals. Choose which files wait for a person to approve them.
Audit log. See who approved each file and when.

The Runstamp console showing a spreadsheet run: one cell changed, Budget B2 from 1200 to 1450, with the input and output side by side and the changed cell highlighted.

The Runstamp console on a phone: one cell changed, Budget B2 now 1450, was 1200.

Only the cells you change

Some spreadsheet libraries drop charts and images when they save a workbook. Runstamp writes the cells you name, then reopens the file to check that nothing else changed.

A wide, perspective view of the Remediation worksheet rendered as pale dots and fine grid lines. Dots in the Status cell at Remediation E2 turn ultramarine as a scan passes; every other cell remains unchanged.

Self-host or use our cloud.

Run the Apache-2.0 SDK on your own servers, or call our API.

No Office install.

Runs on any Node.js server without Microsoft Office or LibreOffice.

Repair corrupted files.

Fix the workbooks that make Excel ask “Do you want us to try to recover as much as we can?”

Pricing

Free to self-host. Pay for support or for our cloud API.

Free

For self-hosting

SDK, CLI and MCP server
No usage limits
Community support

Read the quick start

Pro

For teams self-hosting in production

$199/monthor $1,990/yr

2 named contacts
Reply on blockers within 1 business day
Annual readiness review

See Pro

Platform

For our cloud API

$1,500/monthor $15,000/yr

50,000 successful output files a month
$0.03 per extra output file, if you opt in
Each file a run returns counts once; failed runs are free

Start free trial

Enterprise

For shipping Runstamp inside your product

From $50,000/year

OEM and white-label terms
Volume pricing
Security review

Contact sales

Call it from your code, your terminal or your AI agent

import { runstamp } from "@runstamp/sdk";const changed = await runstamp.operations.run("xlsx.transform", {  workbookBase64, artifactId,  writes: [{ locator, value: "Ready for review" }],});if (!changed.ok) throw new Error(changed.error.remediation);

Node.js SDK

Install it from npm and call it from your app.

$ runstamp ops describe xlsx.transform{ "ok": true, "operation": { … } }$ runstamp ops invoke xlsx.transform \    --input input.json{ "ok": true, "value": { … } }$

CLI

Run it in scripts and CI.

MCP server

Let Claude, Cursor and other MCP clients update spreadsheets and fill PDF forms.

Try it on a sample file

No signup. Change a cell, fill a form or compare two drafts in your browser.

Try it Start free trial

npm install @runstamp/sdk