> For the complete documentation index, see [llms.txt](https://doc.duaer.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://doc.duaer.com/tools/json-to-csv.md).

# JSON to CSV converter (nested JSON flattened)

A free Duaer tool: paste or upload JSON, nested fields become columns, and you download CSV or Excel. It runs in your browser with no upload.

Interactive converter (runs in the browser, no upload): https://doc.duaer.com/tools/json-to-csv/

## How to use it

1. Drop a .json file into the box above, or paste JSON into the text box and click "Convert".
2. Check the column names in the preview.
3. Click "Download .csv" or "Download .xlsx".

## Conversion rules

- Top-level array: one row per element.
- Top-level object with exactly one array of objects (such as `data` or `items` in an API response): that array is used.
- Nested objects become columns like `customer.name`; arrays of plain values are joined with commas; arrays of objects stay as JSON text.
- JSON Lines (.jsonl, one object per line) works too.

## Automate it in Duaer

Want an API response saved as a table every day? In Duaer, fetch it with HTTP Request, split the array with Split Out (see [Split an array into items](/snippets/split-array-into-items.md)), then use [Convert to File](/integrations/builtin/core-nodes/duaer-nodes-base.converttofile.md) › Convert to CSV or write the rows into a sheet.
## Questions

### My JSON is deep and produces too many columns. What now?

The Duaer converter flattens every level. Delete columns in Excel afterwards, or keep only the fields you need with Edit Fields in a Duaer workflow.

### It says the JSON could not be parsed.

Usually a missing comma, single quotes, or a trailing comma. The Duaer converter shows the error position so you can fix it and retry.

## Related

- [Free file converters from Duaer](https://doc.duaer.com/tools.md)
- [CSV to Excel converter (free, no upload)](https://doc.duaer.com/tools/csv-to-excel.md)
- [Excel to CSV converter (UTF-8, no upload)](https://doc.duaer.com/tools/excel-to-csv.md)
- [CSV to JSON converter (free, no upload)](https://doc.duaer.com/tools/csv-to-json.md)
- [Split an array into separate items in Duaer](https://doc.duaer.com/snippets/split-array-into-items.md)