Yes. The first row supplies the object keys, so the input needs a header row plus at least one data row.
Are duplicate headers allowed?
No. Column names must be unique and non-empty so each field maps cleanly to one key. Rename or remove the duplicate column and convert again.
Are numbers converted to JSON numbers?
No. Every value is kept as a string. That is deliberate — it protects leading zeros in IDs, postcodes, and phone numbers, which a type-guessing converter would silently destroy.
Can cells contain commas or line breaks?
Yes, as long as they are wrapped in double quotes, with any inner quote doubled — the standard CSV convention that spreadsheet exports use.
What happens to blank lines or short rows?
Completely blank lines are skipped. A row with fewer cells than headers fills the remaining keys with empty strings rather than failing.
Is my input uploaded?
No. Conversion runs in your browser. Nothing is sent to a NeedAnyTool server for these tools.
