Q: What does “Expected N fields, found M” mean?
A: The row has a different column count than the header. Usually caused by a missing comma, a stray newline inside an unquoted field, or an extra delimiter.
Q: Is my CSV sent anywhere?
A: No. Everything runs in your browser. You can verify by inspecting the Network tab while validating.
Q: Does the validator auto-detect delimiter?
A: Yes. PapaParse infers delimiter from the first few rows. The validator reports field-count mismatches relative to that detected delimiter.
Q: Will it flag BOM or extra whitespace?
A: BOM is handled silently. Whitespace inside fields is considered valid — use the CSV Formatter if you want to trim it.
Q: Which CSV standard is supported?
A: RFC 4180 quoting rules. Fields may be quoted with " and contain embedded delimiters or newlines.