JSON to CSV Converter

1. Paste JSON or open a .json file. The CSV and the table preview update as you type.
2. If the JSON is an object that contains arrays, use Rows from to choose which one becomes the rows. The first array of objects is picked automatically.
3. Choose a delimiter. Use semicolon if the file will be opened by Excel in a locale where the comma is the decimal separator, or tab for a TSV.
4. Choose how nested values are written: flattened into separate columns, or kept as JSON text in a single cell.
5. Click Download. With Excel BOM ticked, the file starts with a UTF-8 byte order mark so accented and non-Latin characters display correctly in Excel. The status bar shows the row and column count.

Each record is walked recursively. Object keys are joined with dots and array positions become numeric segments, so this input:

[
  { "id": 1, "address": { "city": "London" }, "tags": ["admin", "math"] },
  { "id": 2, "address": { "city": "Oslo", "zip": "0150" }, "active": false }
]

produces these columns, in the order the keys were first seen:

id,address.city,tags.0,tags.1,address.zip,active
1,London,admin,math,,
2,Oslo,,,0150,false

The column set is the union of all keys, so a field that appears only in record 2 still gets a column and is blank for the others. null and missing values are both written as empty cells, because CSV cannot tell them apart. An empty array or object is written as [] or {} only when no other record fills that path.

Index paths work well for short, fixed-length arrays such as coordinates. For variable-length arrays, like a list of order items, they create one column per position and a very wide sheet. Choose Keep as JSON text instead to put the whole array in one cell, or convert the inner array on its own with Rows from. If your keys already contain dots, the flattened names are ambiguous, and the JSON text option is safer.

A field is wrapped in double quotes when it contains the delimiter, a double quote or a line break, and embedded quotes are doubled: Grace "Amazing" Hopper becomes "Grace ""Amazing"" Hopper". Rows end with CRLF, as RFC 4180 specifies. Even with correct quoting, Excel changes data when it opens a CSV by double-click:

• Encoding. Without a BOM, Excel may decode UTF-8 as a legacy code page and show é instead of é. The BOM option prevents this.
• Leading zeros. ZIP codes and IDs such as 02134 become 2134. Import through Data → From Text/CSV and set the column type to Text to keep them.
• Long numbers. Excel keeps 15 significant digits, so an 18-digit order ID is shown in scientific notation and its last digits are replaced with zeros. Store long IDs as strings and import them as Text.
• Formulas. Cells starting with =, +, - or @ can be evaluated as formulas. If you export user-supplied data for others to open, read about CSV injection and consider prefixing such values with an apostrophe.

CSV has no types, so true, 42 and "42" all become plain text, and null is indistinguishable from an empty string. Deeply nested or irregular data, such as an order with a variable list of line items each holding options, either explodes into hundreds of sparse columns or ends up as JSON inside a cell. If the consumer is another program, keep JSON, or use JSON Lines for streaming. If you need to look at nested data rather than tabulate it, the JSON viewer is a better fit. CSV is the right choice when the data is genuinely tabular and the destination is a spreadsheet, a database bulk import or a BI tool. Use the CSV to JSON converter to go back, and the JSON formatter to clean up the input first.