About this tool
Spreadsheet tools like Excel and Google Sheets are still where most people actually review and share tabular data, even when it originates as a CSV export or a JSON API response. This tool converts either format directly into a real .xlsz file you can open in Excel, Numbers, or Sheets, with columns automatically inferred from your data — for JSON input, nested objects are flattened into columns and arrays are expanded into rows so the result is a normal flat table rather than a single unusable cell of text. The conversion happens entirely in your browser using JavaScript; your data is never uploaded to a server, which matters if the source file contains customer records, internal reports, or anything you'd rather not pass through a third-party backend.
Frequently asked questions
Does it work with nested JSON?
Yes — nested objects are flattened into dot-separated columns (e.g. address.city) and arrays are expanded into rows, so the output is a usable flat spreadsheet.
What Excel format does it produce?
A standard .xlsx file compatible with Excel, Google Sheets, LibreOffice Calc, and Apple Numbers.
Does it preserve number and date formatting?
Numeric values are written as real numbers rather than text, so they sort and calculate correctly once opened in a spreadsheet.
Can I convert multiple CSV files into one Excel file?
Currently each conversion produces one sheet from one input; combining multiple files into separate tabs of the same workbook isn't supported yet.
Is my data uploaded anywhere?
No — the conversion runs entirely in your browser using JavaScript, and the file is generated locally before you download it.