Is the JSON to CSV converter free?
Yes. This JSON to CSV tool is completely free to use with no signup or account required.
Does it upload my JSON?
No. The conversion runs entirely in your browser on your own device, so your JSON is never uploaded to a server and stays private.
Does it support nested arrays or objects?
No. This version supports flat rows only and clearly rejects nested structures, since flattening requires opinionated column choices.
Can I open the result in Excel or Google Sheets?
Yes. The output is standard CSV with a header row, so it opens directly in Excel, Google Sheets, or any spreadsheet app.
Can I download the CSV right away?
Yes. The converted CSV is ready to copy or download as soon as the conversion runs.
Why does it reject my nested JSON?
Because there is no correct way to flatten it that everyone agrees on. Should a nested object become dotted column names, or JSON-in-a-cell, or exploded into multiple rows? Every answer is right for some case and wrong for others. Rather than guessing on your behalf, the tool refuses and names the field, so you can flatten it the way your destination expects.
What happens when rows have different keys?
The header is the union of all keys across all rows, in the order they were first encountered. A row that does not have one of those keys gets an empty cell for it. That means a ragged array of objects converts without error, and the gaps are visible in the output.
How are commas inside values handled?
The cell is wrapped in double quotes, and any double quote already inside the value is doubled. This is the standard CSV escaping rule and it is what every spreadsheet and CSV parser expects, so a value containing a comma, a newline or a quote survives the round trip.
Why does Excel open my CSV as one column?
Because your Excel is running in a locale that expects the semicolon as the list separator, and this tool always emits commas. The fix is on the Excel side: use Data then From Text/CSV and set the delimiter explicitly, rather than double-clicking the file and letting the locale decide.
How are nulls and booleans written?
A null becomes an empty cell. A boolean becomes the literal text true or false. Neither is quoted unless it needs escaping. If your consumer distinguishes an empty string from a null, CSV cannot carry that distinction, and you will need to substitute a sentinel value before converting.
Is my JSON uploaded?
No. It is parsed and converted in the page, so a payload with real customer data in it never leaves the tab.