CSV ↔ JSON Converter
Convert CSV to JSON or JSON to CSV — free, instant, runs in your browser
Paste into the left panel, upload a file, or click Sample to try it out
Switch between CSV and JSON in one click — set your delimiter, choose whether the first row is a header, flatten nested objects, and preview the output before downloading. Everything runs in your browser; no data ever leaves your device.
How to Convert CSV to JSON (or JSON to CSV)
Upload your file, adjust delimiter and header settings, then download the converted output — all in seconds.
Upload your CSV or JSON file
Drag and drop a .csv or .json file onto the converter, or paste the raw text directly into the input area. Files stay in your browser — nothing is sent to a server.
Set delimiter, header, and flatten options
Choose your column separator (comma, semicolon, tab, or custom), toggle whether row 1 is a header, and optionally flatten nested JSON objects into dot-notation CSV columns.
Preview and download
The live preview updates as you change settings. When the output looks right, click Download to save the converted file.
Features
Runs entirely in your browser — your data never leaves your device
Supports both directions: CSV → JSON and JSON → CSV in one tool
Custom delimiter support: comma, semicolon, tab, pipe, or any character
Toggle header row on/off — works with and without column names
Live preview updates as you type — no submit button needed
Upload a .csv or .json file directly, or paste raw text
Download the converted file instantly as .json or .csv
Handles quoted fields, escaped commas, and multi-line cell values
Free, no sign-up, no file size limits — all processing is local
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Frequently Asked Questions
Does my CSV data get uploaded to a server?
No. All conversion happens inside your browser using JavaScript. Your data never leaves your device — nothing is sent to any server, logged, or stored anywhere.
What delimiters are supported?
Comma (,), semicolon (;), tab, and pipe (|) are available as presets. You can also enter any single character as a custom delimiter — useful for TSV files or non-standard exports.
My CSV has no header row. Will it still convert?
Yes. Toggle 'Header row' off before converting. Without a header row, each record is output as an array of values rather than a named object.
Can I convert a JSON array back to CSV?
Yes. Switch to JSON → CSV mode, paste your JSON array of objects, and the tool builds a CSV with headers derived from the object keys.
What happens with special characters or line breaks inside a cell?
Fields containing the delimiter, double quotes, or newlines are automatically wrapped in double quotes in the CSV output, following RFC 4180. Double quotes inside values are escaped as two consecutive double quotes.
Is there a row or column limit?
No hard limit — the only practical constraint is your browser's available memory.