Paste CSV — or pick a local file — and get JSON with the header row as keys, honoring RFC 4180 quoting and auto-detecting the delimiter; or paste a JSON array and get properly quoted CSV with the columns unioned across objects. Errors name the offending row and column.
Privacy ledger
Data acquired
None.
Libraries used
Lit 3 — bundled into the tool file itself.
Data stored
None.
Data transmitted
None.
Use it on your own page
Download the tool as a single self-contained HTML file: readable source with the Lit library included, zero network requests — it works opened straight from your disk, and you can customize everything.