CSV to JSON

CSV → JSON array · type inference · auto-detect header

Paste CSV, get a JSON array of objects. Header row auto-detected. Type inference recognises numbers, booleans, null, and ISO dates. Toggle Unflatten to turn user.address.city columns back into nested objects. The reverse direction is at JSON → CSV.

First row is a header Type inference Unflatten a.b.c columns

Input CSV

JSON output

Paste CSV.

How to convert CSV to JSON

Paste CSV (header row auto-detected; toggle off if you have no header).
Pick Type inference — Auto (numbers, booleans, null, ISO dates), All strings, or Custom (per-column).
Output is the JSON array. Toggle Unflatten to turn user.address.city columns back into nested objects.

What gets inferred

123 → number; 1.5 → number; "012" stays string (leading-zero numbers are usually IDs).
true / false → boolean.
Empty cell or null → JSON null.
Other text stays as a string.

FAQ

What about embedded newlines?

RFC 4180 CSV allows newlines inside quoted fields. The parser handles them. If your CSV uses unquoted newlines (some legacy exports), pre-clean it.

My phone numbers lose leading zeros — why?

Because type inference saw a number-like string. Switch Type inference to All strings, or wrap such columns in quotes on the export side.

Will it work offline?

Yes — uses PapaParse, loaded once from a CDN and cached.