Online tools
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.
How to use it
- Drop a .json file into the box above, or paste JSON into the text box and click "Convert".
- Check the column names in the preview.
- 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), then use Convert to File › 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.
In this section
Free file converters from Duaer
Free Duaer tools for spreadsheets and data files: convert formats, merge, split, remove duplicates, fix encodings, and format JSON. Everything runs in your browser and no file is uploaded.
File conversionCSV to Excel converter (free, no upload)
A free Duaer tool that turns CSV into .xlsx in your browser. It detects UTF-8 or GBK, keeps long IDs as text, and never uploads the file.
File conversionExcel to CSV converter (UTF-8, no upload)
A free Duaer tool that turns .xlsx or .xls into UTF-8 CSV in your browser. Pick a sheet; a BOM is added by default so Excel reopens it cleanly.
File conversionCSV to JSON converter (free, no upload)
A free Duaer tool that turns each CSV row into a JSON object keyed by the header row. Optional number and boolean detection, GBK support, copy or download.
SnippetsSplit an array into separate items in Duaer
Duaer nodes run once per item. Split an order line list or an API array into one item per entry with Split Out so the next nodes handle each one.