01
Choose a direction
Convert a headed CSV into JSON records or a JSON object array into CSV.
CSV ↔ JSON Converter
Convert CSV to JSON or JSON objects to CSV locally with validation and spreadsheet-safe output.
0 input characters
JSON output
0 output characters
Conversion runs locally in your browser. CSV values become JSON strings; nested JSON values are kept as JSON text in CSV cells.
Your data is processed locally in your browser whenever supported and is not uploaded to our servers.
How it works
Convert structured data in three steps
02
Paste and validate
Add your data and review clear errors before any output is produced.
03
Copy or download
Copy the converted text, download the correct file type, or reverse the conversion.
Predictable conversion
Preserve values without hiding ambiguous data.
Duplicate or empty CSV headers and mismatched rows are reported instead of silently overwriting values. JSON columns follow their first-seen order across every object.
Quoted CSV support
Handles commas, line breaks, quotes, Unicode text, and automatically detected delimiters.
Flexible JSON input
Accepts one object or an array of objects and builds a union of their property names.
Nested data preserved
Objects and arrays are stored as JSON text inside CSV cells instead of being discarded.
Spreadsheet safety
Optional, enabled-by-default protection neutralizes cells that spreadsheet apps may interpret as formulas.
FAQ
Common questions
What JSON shape can be converted to CSV?
Use one JSON object or an array containing objects. Primitive array items are rejected because they cannot form named CSV columns without inventing a schema.
Are CSV numbers and booleans automatically typed?
No. CSV has no universal type metadata, so CSV values become JSON strings. This avoids changing identifiers, leading zeros, dates, or other values based on guesses.
What happens to nested JSON objects and arrays?
They are serialized as JSON text within their CSV cells. This preserves the information, but converting that CSV back to JSON does not automatically infer and rebuild the nested structure.
Why is spreadsheet formula protection enabled?
Spreadsheet apps may execute cells beginning with certain characters as formulas. Protection prefixes those values with an apostrophe. Disable it only when exact formula-like text is required and you trust the data.
Is my data uploaded?
No. Parsing, validation, conversion, copying, and file creation happen locally in your browser.
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