JSON ↔ CSV Converter

Convert between JSON arrays and CSV with nested key flattening, delimiter options, validation errors, a live table preview, and one-click file download — entirely in your browser.

Delimiter:

How to Use the JSON ↔ CSV Converter

  1. Choose direction: Click "JSON → CSV" to convert a JSON array into a spreadsheet-friendly CSV file, or "CSV → JSON" to turn CSV data into a JSON array you can use in code.
  2. Select delimiter: Choose Comma (standard), Semicolon (common in European locales), or Tab (for TSV files). This affects both input parsing and output generation.
  3. Paste your data: Paste your JSON array or CSV text into the left input area. Click "Load Example" to see a sample format.
  4. Click Convert: The result appears in the right panel. For JSON → CSV, a table preview is shown below so you can verify the data looks correct.
  5. Copy or Download: Click "Copy" to copy to clipboard, or "Download" to save as a .csv or .json file.

Frequently Asked Questions

The input must be a JSON array of objects — for example: [{"name":"Alice","score":95}]. Each object becomes one CSV row. Nested objects are flattened using dot notation (e.g., address.city becomes a column header). Arrays within objects are joined with a pipe | separator.
If your JSON contains nested objects like {"user": {"name": "Alice", "age": 30}}, the converter flattens these into dot-notation columns: user.name and user.age. This makes deeply nested API responses usable in spreadsheets without manual restructuring.
The CSV parser correctly handles fields enclosed in double quotes. For example, "Smith, John" will be parsed as a single field containing a comma. Fields with embedded double quotes are also handled following the RFC 4180 standard (double-quote escaping).
There is no enforced limit. However, very large datasets (100,000+ rows) may cause the browser to slow down since all processing happens in-memory in JavaScript. For large files, consider splitting them into batches or using a server-side conversion tool.
Yes. Everything runs in your browser. Your JSON or CSV data never leaves your device and is never sent to any server. This makes the tool safe for confidential business data, API responses with customer information, and sensitive payloads.

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