JSON to CSV Converter Online Free — Convert JSON ↔ CSV Instantly
JSON ↔ CSV Converter converts JSON arrays to CSV spreadsheets and CSV files back to JSON objects. It handles nested JSON objects via dot notation flattening, auto-detects CSV delimiters, and infers data types for numbers and booleans. Convert in both directions and download as .json or .csv files. Everything runs in your browser — your data is never uploaded.
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How to Convert JSON to CSV Online Free
- 01
Choose direction
Select JSON → CSV or CSV → JSON. The Swap button lets you use the output as the next input.
- 02
Paste or upload
Paste your data directly or upload a .json or .csv file. Use the Sample button to try an example.
- 03
Download or copy
The converted result appears instantly. Copy to clipboard or download as the appropriate file type.
Features
- ✓Two-way conversion: JSON arrays → CSV and CSV → JSON objects
- ✓Nested object flattening with dot notation (user.name, address.city)
- ✓Auto-detect CSV delimiter: comma, semicolon, tab, or pipe
- ✓Type inference: "30" → number, "true" → boolean, "null" → null
- ✓Preview table shows first 5 rows of converted CSV output
- ✓Upload .json or .csv files directly from disk
- ✓Swap button: use output as new input for chained conversions
- ✓100% client-side — data never leaves your browser
Frequently Asked Questions
- How do I convert JSON to CSV?
- Paste your JSON array into the input, select "JSON → CSV" direction, and the converter will automatically extract column headers from the JSON keys and produce a properly formatted CSV. Nested objects are flattened using dot notation (e.g., address.city becomes a column header).
- What happens with nested JSON objects?
- When the "Flatten nested objects" option is enabled, nested objects are expanded into dot-separated column names. For example, {"user": {"name": "Alice", "age": 30}} becomes two columns: user.name and user.age. If flattening is disabled, nested objects are serialized as JSON strings in the cell.
- Does CSV to JSON support type inference?
- Yes. When type inference is enabled, the converter automatically converts numeric strings to numbers ("30" → 30), boolean strings to booleans ("true" → true, "false" → false), and "null" strings to null values. Disable this option if you need all values to remain as strings.
- What CSV delimiters are supported?
- The converter supports comma (,), semicolon (;), tab, and pipe (|) as delimiters. When converting CSV to JSON, you can select Auto-detect and the converter will identify the delimiter from the first line of your CSV file.
- Is my data sent to a server?
- No. All JSON and CSV conversion happens entirely in your browser using vanilla JavaScript. Your data is never uploaded to any server and is never stored or logged. The tool works completely offline once the page has loaded.