Which formats can I convert between?

Excel (.xlsx/.xls) to CSV, TSV, semicolon-CSV or JSON — and CSV/TSV back to a styled .xlsx with bold frozen headers.

Does it handle multiple sheets?

Yes — pick any sheet from a workbook, or convert every sheet at once (one file each, or one combined workbook).

Is my spreadsheet uploaded?

No — parsing happens in a background thread of your browser. Financial data never leaves your device.

What about legacy encodings?

Files that aren't UTF-8 (older exports) can be re-read as Windows-1252 with one click.

Excel to JSON Converter Free — In Your Browser, No Upload

A workbook as JSON, one array of row objects per sheet, keyed by the header row. The shape an API or a script actually wants, without a round trip to a server.