What happens when the objects do not all have the same keys?

The header is the union of every key seen anywhere in the array, kept in the order each key first appears. An object missing a key gets an empty cell for it, so no row is silently dropped and no column disappears because the first record happened not to use it. The note under the output tells you how many columns that affected.

Why does Excel show everything in one column?

Excel splits on the delimiter configured for your locale, and many European installs expect a semicolon rather than a comma. Switch the delimiter here to match. Lines are written with CRLF endings for the same reason, that is what Excel wants, so if a later tool complains about stray carriage returns, that is where they came from.

Can I convert a single JSON object?

Wrap it in square brackets first. The input has to be an array; an array of one gives you a header and one row.

JSON to CSV

No upload · runs in your browser

Delimiter

Arrays

JSON in

0 characters

CSV out

Runs entirely in your browser, nothing is uploaded.

How it works

JSON to CSV Converter: Flatten Nested Objects to Columns

Paste a JSON array and get a spreadsheet-ready CSV. Keys are unioned across every object, nested objects become dotted columns, and quoting follows the CSV rules Excel expects.

What this does

Every key that appears anywhere becomes a column, in first-seen order
Nested objects flatten into dotted column names such as address.city
An array cell joins with a semicolon or a pipe, or keeps its JSON if you would rather not lose it
Comma, semicolon, tab or pipe delimiter, with RFC 4180 quoting and CRLF line endings
Row and column counts, and a note naming how many columns were absent from some object

FAQ

Shape. A nested object becomes a column named address.city, and nothing in the CSV records that address and city were ever one thing, read it back and you have a flat record, not the document you started with. Arrays lose more. With the join option every element is glued into a single cell separated by a semicolon or a pipe, so an element containing that character is now indistinguishable from a separator; pick “Keep as JSON” when the array has to survive a round trip. Nesting deeper than twelve levels stops flattening, and whatever is left at that point is written into one cell as JSON.

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