What the free converter does
It takes a JSON array, writes a real .xlsx file with one sheet and a header row, and gives it back. It
runs the same job as the paid JSON to Excel API. No AI is involved.
Limits
- A JSON file up to 1 MB, with an array of up to 500 rows.
- One sheet per file, with the keys of the first row as headers.
- Five runs per day from the same browser.
- Results are deleted within the hour, or at once when you download them.
Questions
What JSON does it accept?
A JSON array of objects, one object per row, up to 500 rows. The keys of the first object become the column headers.
Are formulas run?
No. A cell that starts with =, +, - or @ is written as text, so user data cannot inject a formula into the workbook.
Can I send more than 500 rows?
Yes. The paid JSON to Excel API accepts up to 200,000 rows and sends large files to a background job with a webhook.
Example input
[
{ "id": "W-1001", "item": "Pump seal", "qty": 4, "unit_price": 18.5 },
{ "id": "W-1002", "item": "Gasket", "qty": 12, "unit_price": 2.25 }
]