How the conversion works
The first CSV row is used as the keys, and each following row becomes one JSON object. Quoted fields are parsed per RFC 4180, so values like "Lee, Sam", doubled quotes and line breaks inside a cell are handled correctly. Comma, semicolon, tab and pipe delimiters are detected automatically.
Numbers and booleans
With the option on, 31 becomes the number 31 and true a boolean; empty cells become null. Values with leading zeros like 00123 stay strings so ZIP codes and IDs aren't damaged.
JSON to CSV
Paste an array of objects. The header is the union of all keys, so objects with missing fields still line up. Nested objects are written as JSON text in the cell.
FAQ
Is there a size limit?
It handles several MB comfortably; for very large files use the CSV to Excel tool with file upload.