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HomeToolsFile ConvertersFree JSON to CSV & CSV to JSON Converter
File ConvertersConvert

Free JSON to CSV & CSV to JSON Converter

Convert JSON to CSV and CSV to JSON in one tool. Flatten nested objects, auto-detect delimiters, infer data types, and export files. 100% client-side.

TA
Tanbir Ahamed·Founder of ToolWise · Software Engineer
Published June 2026Updated August 2026

Interactive Tool Workspace

JSON CSV
47 lines · 697 chars

How to Use

  1. 1Choose the conversion direction using the swap button: JSON to CSV or CSV to JSON.
  2. 2Paste your data or upload a .json/.csv file from your computer.
  3. 3Configure options such as delimiter, headers, nested flattening, and type inference.
  4. 4Click Convert to generate the output and review the data preview table.
  5. 5Copy the result or download it as a properly formatted .json or .csv file.

Features

  • ✓Bidirectional JSON to CSV and CSV to JSON conversion in one tool
  • ✓Auto-detect delimiter from CSV content or choose comma, semicolon, tab, pipe, custom
  • ✓Flatten nested JSON objects into dot-notation CSV columns
  • ✓Choose whether the first CSV row is a header or supply custom headers
  • ✓Infer booleans, numbers, null, and nested JSON from CSV cells
  • ✓Wrap single JSON objects into arrays automatically
  • ✓UTF-8 BOM option for correct Excel international character display
  • ✓LF or CRLF line endings for cross-platform compatibility
  • ✓Paginated data preview table before exporting
  • ✓Upload files directly and process them in the browser
  • ✓Download outputs with correct MIME types and extensions
  • ✓100% client-side conversion with no server upload
Comprehensive Guide & Reference

JSON and CSV: A Bidirectional Converter Built for Data Engineers

Most converters handle only one direction. This tool converts JSON to CSV and CSV to JSON in the same interface, with advanced options for delimiters, nested objects, data types, headers and Excel compatibility.

1. Why Bidirectional Conversion Matters

Data pipelines rarely move one way. You export a JSON array from an API, hand it to a data analyst as CSV, receive edits back, then re-import it as JSON. A single tool that handles both directions keeps your workflow inside one tab.

2. Nested JSON to Flat CSV

JSON supports trees; CSV is flat. Flattening converts nested objects into dot-notation columns. Arrays become either JSON strings or comma-separated lists, preserving every value without inventing new rows.

3. Delimiters and Regional CSV

Comma-separated files break in locales that use commas as decimal separators. Switch to semicolon or tab delimiters, or define your own. Auto-detection reads the first lines to guess which character separates your columns.

4. Header Handling and Type Inference

Toggle whether the first row contains headers, supply custom keys, or let the tool generate column names. Type inference turns numeric and boolean strings back into native JSON values, which is critical for APIs that reject quoted numbers.

5. Privacy and Performance

The converter runs entirely in your browser. Files loaded through the upload button are read with FileReader, not sent to a server. You can safely process customer lists, API responses, and configuration files offline.

Conclusion

Done right, the whole operation takes seconds, runs entirely in your browser, and never uploads a byte of your input. For jSON and CSV: A Bidirectional Converter Built for Data Engineers — or anywhere a precise, in-browser result beats a heavier install — this tool is the right one.

Frequently Asked Questions

Does this tool work in both directions?
Yes. Use the swap button to switch between JSON to CSV and CSV to JSON. The same options adapt to the selected direction, so you can round-trip your data without leaving the page.
How are nested JSON objects converted to CSV?
Enable the Flatten nested objects option to turn nested keys into dot-notation columns such as department.name and department.floor. Arrays can be exported either as JSON strings or joined with commas.
Can I use a custom CSV delimiter?
Yes. Choose comma, semicolon, tab, pipe, or enter a custom delimiter. In CSV-to-JSON mode you can also let the tool auto-detect the delimiter from the first few lines.
What happens if my CSV has no header row?
Uncheck First row is header and optionally provide custom column names. If you leave the custom headers empty, the tool generates column1, column2, and so on.
Does CSV to JSON infer numbers and booleans?
By default the tool infers true, false, null, integers, floats, and JSON objects or arrays inside cells. Toggle Infer data types off to keep every value as a string.
How do I open the CSV in Excel correctly?
For European locales, select semicolon delimiter and optionally include a UTF-8 BOM so Excel treats special characters correctly. You can also switch line endings to CRLF for Windows compatibility.

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