Convert JSON to CSV
An array of objects becomes one column per key. Nested objects are written as JSON text in the cell rather than being silently flattened or dropped.
- Runs entirely in your browser
- Works offline
- No upload
- No sign-up
- No watermark
Loading the tool…
How it works
- Drop a .json file, or paste the JSON.
- Choose CSV, TSV or Excel, and whether to add a BOM.
- Download the result.
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
What is the BOM for?
Excel on Windows assumes the system codepage unless a CSV starts with a UTF-8 byte-order mark. Without it, Japanese column names open as mojibake. It is on by default because that is the failure people actually hit.
What happens to nested objects?
They are written into the cell as JSON. Flattening them into dotted column names guesses at your intent and loses arrays, so the tool keeps the data instead.
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.