JSONをCSVに変換

What this tool does

Paste a JSON array of objects and get CSV you can copy or download. The first row is the column names. Cells that contain commas, quotes, or line breaks are quoted.

How to use

1. Paste JSON. The value should be an array, and each item should be an object.
2. Press Convert to CSV.
3. Check the row and column counts.
4. Copy the CSV or download data.csv. Press Clear to remove both boxes.

Examples

• Two people

  An array with {"name":"John","age":30} and {"name":"Sara","age":25} becomes a header name,age and two data rows.

• A comma in a name

  The name Doe, Jane is written as "Doe, Jane" so a spreadsheet does not split it into two columns.

Main features

• Columns are the keys from every object, in the order they first appear.
• A missing key becomes an empty cell.
• null becomes an empty cell. Nested objects and arrays are written as JSON text inside the cell.
• Copy and download stay in the browser.

How it works

The converter reads the JSON in the page. It does not send it anywhere. If one object has a key the others lack, that key is still a column and the other rows get an empty cell. A nested value is JSON.stringify’d so the data is still in the file, as one cell rather than extra columns.

Tips

• If you have one object rather than an array, wrap it in square brackets.
• Open the downloaded file in a spreadsheet and check that quoted cells stayed in one column.

Limitations

A JSON array of numbers, or a single object that is not inside an array, is rejected. Nested objects are not flattened into extra columns. Very large JSON can be slow because it is parsed in the browser.

See the disclaimer for what these tools do not cover.

FAQ

What if the JSON is invalid?

The page says it is not valid JSON and does not invent a CSV.

How are quotes inside a cell handled?

The cell is wrapped in quotes, and each quote inside it is doubled, which is the usual CSV rule.

Is my input sent to a server?

No. The JSON is converted in this tab. It is not uploaded.

How do I open JSON in Excel?

Convert the JSON array to CSV here, download data.csv, and open that file in Excel or Google Sheets. Each object becomes a row and each key becomes a column.

What happens to nested objects?

Nested objects are not flattened into extra columns. Flatten them first if you need each nested field in its own column.