What happens to nested fields?

They are serialised into the cell rather than dropped, so nothing disappears silently. Flatten beforehand if you need one column per leaf.

What if records have different fields?

The header is the union of all keys, and missing values leave the cell empty rather than shifting other columns.

Is there a size limit?

No imposed limit. The file is parsed in your browser, so the practical ceiling is your device's memory.

Convert JSON to CSV

Turn JSON into CSV in your browser. Nothing uploaded, no account, no row limit.

Open the converter

This expects an array of objects — the shape an API usually hands back. The keys across those objects become the header row, and each object becomes a line beneath it.

Where it gets interesting is nesting, because CSV has none. A value that is itself an object or an array has to be represented somehow, and here it is serialised rather than silently dropped, so you can see it and decide what to do. If you need genuinely flat output, flatten the JSON first — a converter that guesses how to unnest your data will guess wrong on the row that matters.

Objects with different keys are handled by taking the union, so a field missing from some records leaves those cells empty rather than shifting the columns out of alignment.

How it works

Drop the JSON on the page
Pick CSV as the output
Download the result

Worth knowing. Nested objects and arrays are serialised into the cell rather than flattened into extra columns. The input needs to be an array of objects; a single object or a deeply nested tree will not map cleanly onto rows and columns.

Questions

What happens to nested fields?: They are serialised into the cell rather than dropped, so nothing disappears silently. Flatten beforehand if you need one column per leaf.
What if records have different fields?: The header is the union of all keys, and missing values leave the cell empty rather than shifting other columns.
Is there a size limit?: No imposed limit. The file is parsed in your browser, so the practical ceiling is your device's memory.

Everything the converter reads and writes →

Runs entirely in your browser. The file is never uploaded, so there is nothing for us to store, log or lose. No account, no watermark, no size paywall.