Is my JSON uploaded?
No. Conversion happens locally in the browser tab.
Convert JSON to CSV
Turn a JSON array into a spreadsheet-ready CSV. Nested keys flattened. Nothing uploaded.
Drop files here or
The two problems JSON to CSV actually has
Converting flat JSON to CSV is trivial, which is why every tool claims to do it. The problems are nesting and raggedness. Real API responses contain objects inside objects, arrays of varying length, and rows that simply lack some keys. Those three cases are where most converters produce columns shifted by one, or crash.
This tool flattens nested objects into dotted column names, joins primitive arrays with a separator, and builds the header from the union of all keys across all rows, so missing values become empty cells rather than shifting the row.
Conversion behaviour
How the awkward cases are resolved.
| Conversion behaviour | Behaviour | Notes |
|---|---|---|
| Nested objects | Dotted column names | A nested key like user.name becomes a column literally named user.name. Depth is unlimited. |
| Arrays | Joined with a separator | Primitive arrays join into one cell. Arrays of objects are flattened with an index. |
| Missing keys | Empty cell | The header is the union of all keys, so an absent key leaves a gap instead of shifting the row right. |
| Quoting | RFC 4180 | Values containing commas, quotes or newlines are quoted, so Excel does not split them. |
| Encoding | UTF-8 with BOM option | Excel needs the BOM to display non-ASCII characters correctly on Windows. |
| Input | Array of objects required | A single object or a nested root is not a table. Wrap it in an array first. |
Common mistakes
Converting a single object
One object is one row with many columns, which is legal but rarely what anyone wants. Wrap it in an array.
Forgetting the BOM for Excel
Without a UTF-8 BOM, Excel on Windows renders accented characters as garbage. This tool can add it.
Losing leading zeros
A string like 007 written unquoted becomes 7 in Excel. Keep it quoted if the zeros matter.
Flattening silently losing data
Deeply nested structures with duplicate leaf names can collide. Check the column count against your expectations.
Assuming array order is preserved
It is, but CSV has no types. What was an array and what was a string become indistinguishable.
Questions
Does it handle nested objects?
Yes, they are flattened into dotted column names such as `address.city`.
What happens to arrays?
Primitive arrays are joined into one cell. Arrays of objects are flattened with indices.
Why is my first column showing weird characters in Excel?
Excel needs a UTF-8 BOM. Enable the BOM option when downloading.
Can it handle a large JSON file?
Yes, limited by browser memory rather than the tool.
Does it validate JSON first?
Yes, invalid JSON reports the parse error instead of producing a broken CSV.
Can I convert CSV back to JSON?
Yes, there is a CSV to JSON tool on this site.
Are column types preserved?
No. CSV is text only, so everything becomes a string once it is in the file.
Need this without a browser tab?
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