Free · Browser-local · No signup
Convert CSV to JSON
Turn a CSV into an indented JSON array of objects in your browser, with stable keys for blank or duplicate headers.
CSV → JSON
The selected CSV and generated download stay in this browser tab.
Output contract
What the JSON converter writes
Each CSV row becomes one JSON object. Column labels become object keys; blank and duplicate source headers receive stable, unique names so no value is overwritten.
The same 50 MB CSV input limit and production parser used by the viewer apply here. The generated file is created only after parsing succeeds.
Plain answers
JSON conversion questions
Is this a real JSON file?+
Yes. The download is valid JSON text created from the parsed CSV table.
Is my CSV uploaded?+
No. The selected file is read and converted in this browser tab. Loading the page, code, or bundled sample still makes ordinary web requests.
What happens to data types?+
All source cells remain strings. This preserves identifiers and leading zeroes and avoids guessing that a date, boolean, or formula-like value has another meaning.