CSV to JSON
Convert CSV with a header row to a JSON array of objects — free, unlimited, and entirely private.
How it works
This tool converts CSV with a header row into a JSON array of objects directly inside your browser tab — no server, no upload, no waiting. Parsing runs in a background Web Worker using papaparse, which handles quoted fields, embedded commas, and different line-ending styles correctly.
The header row becomes the object keys for every subsequent row. If a parse error occurs (like a row with the wrong number of columns), the specific row number is shown in the error message.
Limitations
Every value comes through as a string, even numeric-looking ones — this avoids silently rounding very large numbers, at the cost of you needing to convert types yourself downstream if you need real JSON numbers or booleans.
FAQ
- Is this CSV to JSON converter really free?
- Yes — completely free, with no size limits and no account required. Everything runs in your browser, so there's no server cost to recoup.
- Does it need a header row?
- Yes — the first row of your CSV is used as the JSON object keys for every following row. A CSV without a header row will produce incorrect results.
- Are numbers converted to actual JSON numbers?
- No — every CSV value comes through as a JSON string by default, even ones that look numeric. This is intentional: converting numeric-looking text to real numbers risks silently rounding very large IDs, exactly the kind of precision loss this site's tools try to avoid elsewhere.
- Is my data uploaded anywhere?
- No — conversion happens locally in your browser using a background Web Worker. Nothing you paste here is ever sent over the network, which makes it safe to use with production data.