Convert CSV to JSON
Drop a CSV, check the preview, get JSON. Real CSV parsing, so quoted commas and line breaks inside fields do not fall apart.
- Runs entirely in your browser
- Works offline
- No upload
- No sign-up
- No watermark
Loading the tool…
How it works
- Drop a .csv or .tsv file, or paste the text.
- Confirm whether the first row is a header.
- Convert and download or copy the JSON.
Why nothing is uploaded
Every operation on this page is done by code running inside your browser tab, using the same engine that renders web pages. The file is read from disk into your tab’s memory, transformed there, and written back out as a download. It is never sent anywhere — not to us, not to a third party.
Verify it yourself
- Open your browser’s developer tools (F12) and select the Network tab.
- Load your file and run the tool.
- The only requests you will see fetch the tool’s own code — and, for a few heavy tools, their open-source engine from a public CDN — plus one small page-view ping to loreatec.jp (page address and title, nothing more). None of them carry your file.
Frequently asked questions
Are numbers converted to numbers?
No — every value stays a string. Silent type coercion is where CSV pipelines break: a postcode like 0123 becomes 123, and a product code like 1E5 becomes 100000. If you need typed values, convert them where you know the schema.
Which delimiters are supported?
Comma, semicolon, tab and pipe are detected automatically on input; you choose the delimiter on output.
My Japanese CSV opens as garbled text elsewhere. Here?
The encoding is detected: UTF-8 first, and if the bytes are not valid UTF-8, Shift-JIS, then EUC-JP. CSV exports from Japanese banks, municipal systems and older software are usually Shift-JIS without saying so — that is the file that turns to mojibake in tools that assume UTF-8.
Is my document uploaded?
No. The file is read and converted inside this browser tab, on your own device. You can open the page, turn off the internet, and it still works. For a contract or a customer list, that is the guarantee that matters.