CSV ↔ JSON

Move between spreadsheet rows and JSON records, with clear rules for headers, empty cells and nested values.

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Review the output before using it.

Know what happens to your data.

CSV cells stay strings. JSON to CSV keeps nested values in JSON-encoded cells; null and missing values both become empty cells. Spreadsheet protection adds an apostrophe to formula-like text.

Practical limits

Inputs up to 1 MiB, 80 nested levels and 50,000 structured values. CSV supports up to 10,000 data rows and 200 columns. Very large jobs time out so your browser stays responsive. Uploaded files must be UTF-8 text.

Nothing is submitted to a processing server or saved as input history. Copy or download your result before leaving the page. Read the privacy details.