CSV to JSON
Convert CSV rows to JSON with quoted-field support and strict validation.
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When to use csv to json
- Prepare test fixtures from a spreadsheet export.
- Transform small tabular datasets without uploading them.
How it works
A strict state-machine parser supports quoted delimiters, escaped double quotes, quoted newlines, CRLF and a UTF-8 BOM. Header mode produces an array of objects; otherwise output is an array of arrays.
Supported inputs and limits
Up to 2 MiB, 50,000 rows, 500 columns and 250,000 cells. Estimated JSON output is capped at 8 MiB. All cells remain strings, preserving leading zeros. Header names must be non-empty and unique. Row widths must match. No nested JSON inference or spreadsheet formula evaluation occurs.
Common questions
Why are numbers in quotes?
CSV has no reliable type schema. Preserving strings avoids corrupting IDs, dates and leading zeros.
How do I include a comma inside a cell?
Quote the field, such as "London, UK". Inside a quoted field, write a quote as two quotes.
Methodology reviewed 2026-09-09. Processing details and test approach.