Convert CSV or TSV to JSON and back. Nested objects flatten to dotted columns; quoted fields and custom delimiters are supported.
The delimiter is detected automatically from the first non-empty line, so comma, semicolon and tab files all work without configuration.
Quoted fields containing commas, quotes and newlines are parsed per RFC 4180. Nested JSON objects flatten to dotted headers such as user.name, and those columns nest again when you convert back.
Arrays stay in a single cell as JSON, because a list of items does not map cleanly onto one CSV row.
Can I convert an Excel file? Export it as CSV first. This tool reads text formats only, which keeps everything inside your browser.
What happens to nested JSON? Objects become extra columns with dotted names (address.city). Arrays of values stay as a JSON list in one cell so the row count does not change.