CSV to JSON Converter

Convert between CSV and JSON formats instantly. Supports custom delimiters, nested objects, auto number detection, and flattening. 100% client-side — your data never leaves your browser.

100% Client-SideNo UploadFree ForeverNo Sign-up
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How to Convert CSV to JSON

Paste your CSV data into the input panel or click the Upload button to load a .csv file. The tool converts your data to JSON in real time as you type or edit. Choose between Array of Objects (each row becomes a JSON object with header keys), Array of Arrays (raw rows), or Nested Object format (dot-notation headers like address.city become nested structures).

To convert JSON back to CSV, toggle the mode to JSON to CSV. The tool accepts any JSON array of objects or arrays and generates properly quoted CSV output. Enable the Flatten Nested option to convert nested objects into dot-notation columns. All processing runs entirely in your browser using native JSON.parse and JSON.stringify — no data is ever sent to a server.

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Frequently Asked Questions

Paste your CSV data into the input panel or upload a .csv file. The tool instantly converts it to JSON. You can choose the output format (Array of Objects, Array of Arrays, or Nested Object), toggle header detection, and select your delimiter. The JSON output appears in real time.
Yes. Click the mode toggle to switch to JSON to CSV mode. Paste your JSON array and the tool will generate properly formatted CSV output with headers and your chosen delimiter.
Yes. When converting JSON to CSV, enable the Flatten Nested option to flatten nested objects into dot-notation columns (e.g., address.city). When converting CSV to JSON, you can choose the Nested Object output format.
Absolutely. All conversion happens 100% in your browser using JavaScript. Your data never leaves your device and is never sent to any server. There are no uploads, no tracking, and no storage of your data.
The tool supports comma (,), tab, and semicolon (;) delimiters. You can select your delimiter from the options panel. The tool also correctly handles quoted fields containing delimiters and escaped quotes.

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