JSON to CSV Converter

When you need this

Spreadsheets are still the lingua franca of business data, and CSV is what they read. Converting JSON to CSV lets you take an API response and open it in Excel, Google Sheets, Numbers or LibreOffice Calc.

How the conversion works

The tool collects the union of all keys across every object in the array, in the order they first appear. Rows missing a key get an empty cell, and rows with extra keys get their own columns.

[{"id": 1, "name": "Ada"}, {"id": 2, "name": "Alan", "role": "Engineer"}]

becomes

id,name,role
1,Ada,
2,Alan,Engineer

Nested objects

Nested objects and arrays are serialised to JSON strings inside the cell, so nothing is lost:

id,address
1,"{""city"":""London""}"

If you need proper nesting flattened into separate columns, transform the data first with a tool like jq:

jq '.[] | {id, city: .address.city}' data.json

Quoting rules

The tool follows RFC 4180: a value is wrapped in double quotes if it contains a comma, a double quote, or a line break, and embedded quotes are doubled. This is what makes the output safe to open in Excel without corrupting columns.

Tip for large files

For datasets that would choke a browser tab, jq is much faster:

jq -r '.[] | [.id, .name] | @csv' data.json > output.csv

The @csv operator applies the same RFC 4180 quoting rules.