Your spreadsheet is the API.
Upload it, mark inputs and results, publish. Your formulas keep calculating as in Excel, for apps, websites and AI assistants.
Free Basic plan · no credit card · your formulas are never rewritten
Change a value. The workbook answers.
This calculator is a published SpreadAPI service. Nothing here was programmed: the prices, tiers and tax rules live in an Excel file.
Term: 12 months
Try 50 licenses or another edition: the price tiers come from the workbook, not from this page.
- Unit price per month
- $45.00
- Net per month
- $1,096.54
- Net total
- $13,158.48
- Sales tax
- $953.99
See the call: the request and the full JSON answer
An example, not a live call: the request for the values above and the shape of the answer.
https://spreadapi.io/api/v1/services/{serviceId}/execute?licenses=25&edition=Business&discount=0.05{
"service": {
"id": "{serviceId}",
"name": "Quote Calculator"
},
"inputs": [
{
"name": "licenses",
"value": 25
},
{
"name": "edition",
"value": "Business"
},
{
"name": "discount",
"value": 0.05
}
],
"outputs": [
{
"name": "total",
"title": "Total incl. tax",
"value": 14112.47
}
]
}One publish, four ways out.
The same workbook answers code, AI assistants, website visitors and your automations.
REST API
One endpoint per workbook, with an OpenAPI description, tokens and batch calls.
Excel to API →AI assistants
ChatGPT and Claude ask your spreadsheet instead of guessing. Same inputs, same result.
Excel MCP server →Web calculator
A ready-made calculator, shared by link or embedded in your website. No front end to build.
Excel web calculator →Automation
A calculation step in n8n, Zapier and Power Automate, or a formula in Excel and Google Sheets.
Logic in workflows →Three steps, about a minute each.
Import your Excel file
All sheets, formulas and formats arrive as they are. Lookups and dynamic arrays keep working.
Mark inputs and results
Click a cell, add it as a parameter. Names, types and allowed values come from the sheet.
Publish
The service is live. Change a price in the workbook, republish, and every caller gets the new number.
Built for both sides of the spreadsheet.
Developers
The spreadsheet is the back end. You stop rebuilding someone else's formulas in code, and stop fixing them every time a price changes.
- One endpoint, an OpenAPI file, cURL, JavaScript and Python examples
- A real spreadsheet engine: same inputs, same outputs
- Tokens per service, usage log, on-premises runtime as an option
Pricing, finance and product teams
You keep working in Excel. Change a rate, republish, done, without an IT ticket. One checked calculation in one place instead of twenty copies of a file by email.
- Share the result, not the file: your formulas stay with you
- A web calculator for customers and colleagues, ready to send
- ChatGPT and Claude answer with your numbers
Honest about what it is.
A good fit
- Price, quote and tariff calculators
- Commission, fee and loan calculations
- Calculations an AI assistant must get exactly right
- A model that changes often and lives in Excel
Not what it does
- Macros and VBA do not run
- A few newer or data-connected functions are missing
- No approval workflows or sign-off
- Links to other workbooks are not followed
- A chart is not a result; its numbers are
Plans
- Basic · €0
- 1 published service, 1,000 calls a month
- Pro · €99
- unlimited services, 10,000 calls a month
- Custom
- more calls, larger workbooks, on-premises
Bring the workbook you already trust.
Your first service is free and takes about ten minutes. No credit card.