Convert a JSON array of objects into a clean RFC 4180 CSV: header row, CRLF records, correct quoting and quote-doubling. Nested objects flatten to dot-notation columns (a.b.c), arrays are JSON-encoded into their cell, and you can select and order columns explicitly. Delimiter: comma, semicolon, tab or pipe. Caps: 100,000 rows, 5 MB body, 20 MB CSV out. Returns text/csv ready for Excel, Google Sheets or a data pipeline.