JSON to CSV converter

Paste a JSON array of objects, the shape most APIs return, and each object becomes a row and each key a column:

[{"name": "Emily Johnson", "city": "Austin", "age": 34, "address": {"zip": "78701"}}]

becomes

• Nested objects are flattened into dotted column names like address.zip.
• Arrays of simple values become a comma-separated list in one cell; arrays of objects are kept as JSON text.
• If objects have different keys, every key gets a column and missing values are left empty.
• If you paste a single object that contains exactly one list of records (for example {"data": [...]}), that list is used.

Switch the direction and paste CSV with a header row. Each row becomes a JSON object whose keys come from the header. The delimiter is detected automatically, or you can pick comma, semicolon or tab yourself.

With Detect numbers and true/false on, values like 34, -2.5, true and false become real JSON numbers and booleans instead of strings. Turn it off when you need to keep leading zeros, for example in ZIP codes like 02134, product codes or phone numbers.

Quoted fields are handled according to RFC 4180, so commas and line breaks inside quotes stay part of the value.

JSON is the native format of web APIs and JavaScript. It handles nested data, lists, types (numbers, booleans, null) and Unicode cleanly, which makes it the right choice for configuration, API payloads and anything a program reads.

CSV is the lowest common denominator for tables. Every spreadsheet, database and BI tool can import it, it is easy to scan by eye, and it stays small for large numbers of rows. It is the format to hand to a colleague who wants to filter, sort or chart data in Excel or Google Sheets.

A typical workflow: call an API, save the JSON response, convert it to CSV here, and open it in a spreadsheet for analysis. If you then need to send corrected data back to the API, convert the edited CSV back to JSON.

• Google Sheets: File → Import → Upload, then let Sheets detect the separator.
• Excel (US settings): double-click the downloaded .csv file. Comma is the default list separator in US regional settings, so columns split correctly.
• Excel with European regional settings expects semicolons. Choose Semicolon as the delimiter if your colleagues use those settings.

If accented characters look garbled in Excel, the file was read with the wrong encoding. Use Data → From Text/CSV and choose UTF-8, or open the file in our CSV viewer and save it with a byte order mark (BOM).

• Check your JSON first: if conversion fails, the error message points to the problem. The JSON formatter shows the exact line and column.
• CSV has no types: everything is text until a program interprets it. Dates and long numbers may be reformatted by Excel when you open the file.
• Deeply nested data, such as orders containing line items, does not fit a flat table well. Consider exporting one CSV per level.
• Everything runs locally in your browser. Customer lists and exports never leave your computer.