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JSON ⇄ CSV Converter

A free tool to convert between JSON arrays and CSV in both directions. Choose the delimiter, control headers, and flatten nested objects. All processing happens in your browser, so your data is never sent to any server.

Last updated: 2026/10/16 Developer Feedback & bug reports
Your data is never uploaded All conversion happens locally in your browser. No upload, unlimited use, and no sign-up - safe even for confidential data.

How to Use

1

Pick a tab and enter data

Choose the "JSON → CSV" or "CSV → JSON" tab, then type or paste your source data. You can also try the sample button.

2

Set options

Choose the delimiter (comma/tab/semicolon), toggle the header row, and enable nested-object flattening as needed.

3

Convert & copy

Press "Convert" to see the result, then copy it or download it as a file.

About the JSON ⇄ CSV Converter

An online tool to convert between JSON arrays and CSV (comma-separated values) in both directions. Turn JSON fetched from an API into a table format (CSV) you can open in Excel or Google Sheets, or convert CSV into JSON that is easy to use in code. It supports choosing the delimiter, controlling the header row, and flattening nested objects using dot notation. The biggest advantage is that your data is never sent to a server. Everything runs entirely in your browser, so even confidential data such as customer lists or business records can be converted safely, with unlimited use and no sign-up.

Features

  • Two-Way ConversionJSON → CSV and CSV → JSON with a single click. Just switch tabs.
  • Flexible OptionsFine-tune the delimiter (comma/tab/semicolon), header handling, and JSON pretty-printing.
  • Nested FlatteningFlatten nested objects into "key.subkey" dot-notation columns for CSV output.
  • Browser-Only ProcessingData is never uploaded; everything runs on your device. Safe even for confidential data.

Use Cases

  • Convert API JSON into CSV to open in Excel or Google Sheets
  • Turn a customer or inventory CSV into JSON for use in code
  • Reformat database export results
  • Prepare data before importing into no-code or BI tools
  • Convert the format of test or mock data

Related Tools & Guides

To eyeball your data as a table before or after conversion, use the CSV Viewer; to convert JSON for config files, try the JSON ↔ YAML converter; and for formatting or syntax-checking JSON, use the JSON Formatter. To learn how CSV works from the ground up, read the CSV basics guide, and to understand comma- vs tab-separated (TSV) files, see the CSV vs TSV guide.

FAQ

Is my data uploaded to a server?
No. All conversion happens locally in your browser. Your input data is never sent to or stored on any server, so even confidential data is safe.
Can it convert nested JSON to CSV?
Yes. Enable "Flatten nested objects" to expand nested objects into dot-notation headers like "parent.child" in the CSV. Array values are stored as JSON strings inside the cell.
Can I change the delimiter?
Yes. Choose from comma (,), tab, or semicolon (;). This supports semicolon-separated CSVs common in Europe as well as tab-separated values (TSV).
Can it handle commas or line breaks inside CSV data?
Yes. Following RFC 4180, commas, line breaks, and escaped quotes ("") inside double-quoted fields are parsed and produced correctly.
Can it convert a CSV without a header row?
Yes. For CSV → JSON, turn off "Treat first row as header" to handle each row as an array; column names are auto-assigned as field1, field2, and so on.
Can I rebuild a flattened CSV back into nested JSON?
Yes. For CSV → JSON, turn on "Rebuild nested objects from dot-notation keys" to restore a CSV with dotted headers like "parent.child" into JSON with nested objects. Combined with "Flatten" in JSON → CSV, you get round-trip conversion between nested JSON and a table.
How are JSON arrays converted to CSV?
Use the "Array handling" option. "Keep as JSON string" stores each array as a [ ... ] JSON string in the cell so it round-trips without data loss, while "Join values" joins array elements with a semicolon for a more human-readable cell.

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What Is CSV? Delimiters, Quotes, and How to Avoid Garbled Text Learn what CSV is from the ground up: comma delimiters, quoting, line breaks, why text gets garbled when you open files in Excel and how to avoid it, plus practical uses like viewing and JSON conversion. CSV vs TSV: Delimiters, Quoting, Encoding, and When to Use Each A clear guide to the difference between CSV and TSV: comma vs tab delimiters, how quoting handles values containing commas or line breaks, character encoding pitfalls, tips for importing CSV into Excel, when TSV is handy, and how both compare to JSON.