JSON Tool 07

JSON to CSV (and back)

Convert a JSON array into CSV with real RFC 4180 quoting, or parse CSV back into JSON — pick the delimiter, flatten nested objects and keep quoted newlines intact.

JSON Paste JSON to convert

Paste a JSON array of objects

Nested objects stay in one cell as JSON text
CSV Result appears here

CSV appears here

Fields are quoted only when they need to be
Waiting for input Need to eyeball the data first? View it as an HTML table → Client-side only

Frequently asked

What does the tool do with nested objects and arrays?
By default a nested object or array is written into one cell as JSON text, so nothing is lost. Turn on "Flatten nested" to spread them into dotted columns such as user.address.city, and choose whether array values stay as JSON text or get their own numbered columns.
Does it handle CSV with commas or line breaks inside quoted fields?
Yes. The parser implements RFC 4180, so a quoted field may contain the delimiter, line breaks and doubled "" escapes, and it will come back as a single value rather than split into extra rows.
Why does 00123 turn into 123 when I convert CSV to JSON?
It does not, by default — every CSV value comes out as a string, and "00123" stays a string. Turning on "Infer types" converts numbers and booleans, but values with leading zeros are deliberately left as text, so product codes and phone numbers cannot be mangled by accident.
How are missing keys and null values represented?
Both become an empty cell. CSV has no null, so a key that is absent in one object and a key set to null look identical in the output — that distinction survives only in the JSON direction.
Is my data uploaded to a server?
No. Parsing and CSV assembly are plain JavaScript in the page, and the download is generated locally from a Blob. There is no upload endpoint to send it to.