How are nested JSON objects handled?

Nested keys are flattened using dot notation. For example, {"user": {"name": "Alice"}} becomes a column header 'user.name'.

What happens to JSON arrays inside objects?

Arrays of primitives are joined with a semicolon. Arrays of objects trigger a warning — only the top-level array of objects is converted to rows.

Can I change the column delimiter?

Yes — choose comma, semicolon, tab, or pipe from the delimiter dropdown before converting.

How does type detection work for CSV → JSON?

Values that look like numbers are parsed as Number, 'true'/'false' become Boolean, and everything else stays a String. Empty cells become null.

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JSON to CSV / CSV to JSON (Enhanced)

Convert JSON to CSV and CSV to JSON with nested object flattening and smart type detection.

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このツールについて

A two-direction converter for JSON and CSV data. JSON → CSV flattens nested objects using dot notation for keys and handles arrays of objects correctly. CSV → JSON auto-detects the header row and parses values into the right type (number, boolean, or string). Configure the delimiter (comma, semicolon, tab, pipe), quote character, and whether to include a header row. Preview the first five rows of the result before downloading the converted file.

使い方

1 Paste your JSON array (or CSV text) into the input panel.
2 Select the conversion direction: JSON → CSV or CSV → JSON.
3 Choose delimiter, quote character, and header row options.
4 Click 'Convert' to see a preview of the first 5 rows.
5 Click 'Download' to save the full converted file.

このツールについて

使い方

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