CSV is the language of spreadsheets and data exports; JSON is the language of APIs and web applications. Moving data between the two is one of the most common tasks in data work — importing a price list into an app, feeding spreadsheet data to a script, or flattening an API response so Excel can open it.
This converter transforms CSV to JSON (using the first row as keys) and JSON arrays back to CSV. It runs entirely in your browser, so customer lists and financial exports never leave your machine.
How to Use This Tool
- Paste CSV (with a header row) or a JSON array of objects.
- Click the conversion direction you need.
- Review the output — column names become JSON keys and vice versa.
- Copy the result or paste it into your spreadsheet or code.
Frequently Asked Questions
How are commas inside values handled?
Standard CSV wraps such values in double quotes: 'Paris, France' becomes "Paris, France". The parser respects quoted fields, and quotes inside quoted fields are escaped by doubling them.
What JSON structure does the converter expect?
An array of flat objects: [{"name": "Alice", "age": 30}, ...]. Each object becomes a CSV row and each key becomes a column. Deeply nested objects need flattening first, since CSV has no concept of nesting.
Why did my leading zeros disappear?
That happens in spreadsheet apps, not in this converter — Excel interprets 00123 as the number 123. To preserve leading zeros (postal codes, phone numbers), format the column as text when importing the CSV.