CSV ↔ JSON Converter

How It Works

CSV format (RFC 4180): Rows are separated by newlines, fields by the chosen delimiter. Fields containing the delimiter, double quotes, or newlines must be wrapped in double quotes. A literal " inside a quoted field is escaped as "".

CSV → JSON: The first row is used as object keys unless "First row is header" is off. Type inference converts numeric strings to numbers, true/false to booleans, and empty/null to JSON null — toggle it off to keep everything as strings.

JSON → CSV: Accepts an array of objects or an array of arrays. Nested objects are flattened with dot-notation keys. All unique keys across all rows become column headers, so sparse objects produce empty cells for missing fields.

Common pitfalls: Commas inside values must be quoted — "New York, NY". A trailing newline at the end of the file does not add a blank row. Leading zeros in numbers (e.g. 007) are converted to integers by type inference; disable it to preserve them as strings.