Convert CSV to JSON Online — Free & Instant

Paste CSV data and get a formatted JSON array — no upload needed.

How It Works

1Paste your CSV (with or without a header row) into the input area.
2Click Convert to JSON to parse the rows into an array.
3Copy or download the resulting JSON.

About CSV to JSON

Have CSV data from a spreadsheet, database export, or log file that you need as JSON? Many APIs, configuration systems, and modern web applications expect JSON input, but your data might be in CSV format. This tool parses your CSV with automatic delimiter detection (commas, tabs, semicolons) and converts it to a clean JSON array of objects, using the first row as property keys. It correctly handles quoted fields, escaped commas, multiline values, and other CSV edge cases that trip up manual conversion attempts. Copy the result to your clipboard or download it as a .json file. Common use cases include preparing data for API imports, converting spreadsheet data for use in web applications, transforming log files into structured JSON for analysis, and migrating data between systems with different format requirements.

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Frequently Asked Questions

Is my data sent to a server?

No. All processing happens locally in your browser. No data leaves your device.

Does it use the first row as keys?

Yes. The first row of the CSV is treated as column headers and used as the property names in each JSON object.

Can I paste CSV text directly?

Yes. You can paste CSV content into the text area or upload a .csv file. Both methods produce the same JSON output.

How are numeric values handled?

Values that look like numbers are automatically converted to JSON numbers. Everything else is kept as a string.

Does it handle quoted fields with commas?

Yes. The parser correctly handles fields enclosed in double quotes, including fields that contain commas, newlines, or escaped quotes.

Is my file uploaded to a server?

No. Transmute processes everything locally in your browser using JavaScript and the Canvas API. Your files never leave your device — there is no server, no upload, no cloud processing.

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