100% client-side — files never leave your device

Convert CSV to JSON online

Free CSV to JSON converter — header detection, automatic typing and RFC 4180-correct parsing, entirely in your browser. No upload, no signup.

Drop a CSV, TSV or JSON file hereor click to browse — you can also paste data below

      How to convert CSV to JSON

      1. Open or paste your CSV data. Drop a .csv file into the box, or paste rows straight into the input pane — the format is detected from the file name and the first line.
      2. Check the options. Confirm the From and To formats, say whether the first row is a header, and choose pretty-printed or compact JSON.
      3. Press Convert and download. The JSON result appears in the output pane beside your input; press Download .json to save it from your browser.

      About the formats

      CSV

      CSV (comma-separated values) is the lingua franca of tabular data: one row per line, commas between fields. Every spreadsheet, database and analytics tool imports and exports it, which makes it the default for moving tables between systems.

      JSON

      JSON is the standard data format of APIs and modern applications: nested objects and arrays with real types — numbers, booleans, null. Converting tabular JSON (an array of objects) to CSV makes it spreadsheet-friendly; the reverse turns spreadsheet exports into API-ready payloads.

      Frequently asked questions

      Is my CSV data uploaded anywhere?

      No — parsing and conversion happen entirely in your browser. Spreadsheet exports, API payloads and log data never leave your device.

      How do I convert CSV to JSON?

      Drop your CSV file (or paste the data), check the options — header row, pretty-printing — and press Convert. The JSON result appears instantly and downloads from your browser.

      Are quoted fields, commas and newlines inside values handled?

      Yes. The parser follows RFC 4180: quoted fields, escaped quotes and embedded newlines all convert correctly.

      Do values keep their types in the JSON output?

      CSV stores everything as text, so cells that read as a number, true, false or null become real JSON values and everything else stays a string. The number test follows the JSON grammar, so a zero-padded code such as 0012 stays a string while a bare 12 becomes a number — worth checking if your IDs are numeric and the consumer expects strings. Untick “First row is a header” to get an array of arrays instead of an array of objects.

      My file is large — is the whole thing converted?

      Yes. The two panes only display the first 100,000 characters so typing stays responsive, but the conversion and the downloaded file always use the complete input. Everything is held in memory, so extremely large files are still better handled by a script.

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