JSON to CSV Converter

JSON arrays to CSV and back, with a live table preview and Excel-friendly output.

Runs locally · nothing uploaded
JSON
CSV 
Table preview 
The table appears here once the input converts.
What it does
Turn an API response or a JSON export into a spreadsheet-ready CSV, or turn a CSV file into JSON. A table preview shows exactly how the rows and columns come out.
JSON → CSV
  • Every key becomes a column, even when it only appears in some rows. Columns keep the order in which keys first appear.
  • Nested objects are flattened into dot paths (address.city), or kept as JSON text if you turn flattening off. Arrays are written as JSON strings (["admin","billing"]).
  • Wrapped responses work: for {"data": [ ... ]} the rows inside data are used.
  • Correct quoting for delimiters, quotes, line breaks and leading or trailing spaces.
  • Comma, semicolon, tab or pipe, CRLF or LF line endings, and an optional UTF-8 BOM so Excel shows accented characters correctly.
CSV → JSON
  • RFC 4180 parsing: quoted fields, doubled quotes ("") and line breaks inside quotes.
  • Delimiter auto-detection, header row on or off (without a header you get arrays).
  • Type inference (optional): numbers, true/false, empty cells as null and JSON arrays/objects in cells. Values like 007 stay strings so leading zeros are not lost.
  • Unflatten dot paths back into nested objects, so a CSV made here converts back to the original JSON.
  • Unterminated quotes are reported with the line number; rows with a different number of fields are listed as a warning.
Privacy
Everything runs in your browser and nothing is uploaded. Your last input for each direction is kept in local storage.