Overview
Two worlds run on two formats. Developers trade JSON; spreadsheet users live in CSV. Every time data crosses that border — an API export that needs to land in Excel, a spreadsheet that needs to become a config file — someone has to translate. This tool is the border crossing: paste one format, get the other, correctly.
Correctly matters more than it sounds. CSV looks simple until a field contains a comma or a quote, and then naive conversion corrupts the data. The converter applies the real quoting rules — quoting fields that need it, doubling embedded quotes — so the round trip is lossless.
Why do these two formats keep colliding?
Because they optimise for different readers. JSON preserves structure — nested objects, arrays, typed values — which programs need. CSV preserves none of that, but any spreadsheet, database importer and non-programmer can open it. Neither is going away, so translation between them is permanent plumbing.
The friction point is shape. JSON can be nested three levels deep; CSV is resolutely flat — rows and columns. The converter works with arrays of flat objects, the shape both formats genuinely share, and flattens sensibly where it can.
Features
- Two-way conversion: JSON → CSV and CSV → JSON on one page.
- Correct CSV quoting for fields containing commas, quotes or newlines.
- Automatic header row derived from the JSON keys.
- Handles nested values by serialising them rather than dropping them.
- Copy or download the result as text or a .csv file.
- Fully private: your data never leaves the browser.
Benefits
- Open API data in Excel without writing a script.
- Feed spreadsheets to code by converting back to JSON.
- Trust the quoting — commas inside fields will not break columns.
- No row limits or sign-ups standing between you and the file.
Who can use it
Analysts pulling API exports into spreadsheets, developers seeding databases from CSV files, marketers turning a contact list into JSON for a tool, students learning both formats by converting between them, and anyone handed data in the wrong shape. If you have ever retyped a table by hand, this page is for you.
How to use
- Choose the direction: JSON → CSV or CSV → JSON.
- Paste your data into the input box.
- Check the preview — headers, rows and quoting should look right.
- Copy the result or download it as a file.
- Open the CSV in your spreadsheet, or feed the JSON to your code.
Frequently asked questions
What shape of JSON converts best?
An array of flat objects — [{name: 'A', age: 3}, ...]. That maps naturally onto rows and columns. Nested objects get serialised into their cells rather than expanded, and single objects get wrapped as one row. Deeply nested trees are better explored in the JSON formatter first.
How are commas inside fields handled?
By the CSV standard's quoting rule: any field containing a comma, quote or newline is wrapped in double quotes, and any quote inside it is doubled. So the value She said "hi", loudly becomes "She said ""hi"", loudly" — ugly to read, but every proper CSV reader parses it back exactly.
Will Excel open the downloaded file correctly?
Yes — the output is standard CSV with a header row, which Excel, Google Sheets and LibreOffice all open natively. If Excel misreads non-English characters, re-save the file with UTF-8 encoding; that is an Excel quirk, not a problem with the data.
Can I convert CSV without a header row?
The converter expects the first row to name the columns, since JSON objects need keys. If your CSV has no headers, add a first row with column names before converting — generic ones like col1, col2 work fine.
Is my data uploaded anywhere?
No. Conversion is pure string processing in your browser. Spreadsheets with names, emails or figures stay on your machine.
Conclusion
Data should not need a passport to cross from code to spreadsheet. Paste it in the wrong shape, get it back in the right one — quoting intact, headers in place.