CSV / JSON Converter

Maximum 1 MB UTF-8. CSV fields are strings by default, preserving 001 and long integers. Optional typing only converts safe integers and true/false. JSON: flat objects with headers, arrays without headers. Quote large integers in JSON; unsafe numeric integers are rejected. Nested values are unsupported. CSV formula protection changes affected fields by adding an apostrophe; disabling it can activate spreadsheet formulas.

Example: id,name 001,花子 → [{"id":"001","name":"花子"}]