TOOL · DEV
Convert CSV to JSON (and JSON to CSV)
Paste the content or drop the file and take the finished conversion, with a table preview — we detect the separator and respect the quotes.
or drop a file
The conversion happens in your browser — neither the text nor the file is sent.
Processed in your browser — your files never leave your computer.
How it works
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Pick the direction and hand over the content
CSV → JSON or JSON → CSV on the buttons. Paste the text in the box or drop a .csv/.json file up to 20 MB.
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Check the options and click "Convert"
On CSV → JSON, mark whether the first row is the header — the separator (comma, semicolon or tab) is detected automatically, and quoted fields with commas or line breaks inside just work.
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Review the preview and download
The table shows the first 10 rows so you can check the columns landed right. Then copy the result or download the .json/.csv.
Frequently asked questions
Which separators can the CSV use?
Comma, semicolon or tab — the tool counts which one appears most in the first line (outside quotes) and uses that. Excel in many locales exports with semicolons, and it works straight away, no configuration.
Do fields with commas, quotes or line breaks inside work?
They do. The parser follows the CSV rule: a double-quoted field may contain separators and line breaks, and quotes inside a field come doubled (""). On the way back (JSON → CSV), fields that need it are automatically protected with quotes.
What is the "first row is the header" toggle for?
Checked, the first row becomes the JSON keys: each CSV row turns into an object, like {"name":"Ann","age":"31"}. Unchecked, the result is an array of arrays, everything as it came. A column without a name gets "coluna_N".
How must the JSON look to become CSV?
An array of objects: [{"name":"Ann"},{"name":"Bea"}]. One level of nested object is flattened with a dot — {"address":{"city":"SP"}} becomes the "address.city" column. Deeper structures and arrays become JSON text inside the cell.
What is the size limit?
Files up to 20 MB — beyond that the browser would freeze processing everything in memory. Bigger spreadsheet? Split it into parts or export only the columns you need before converting.
Is my data uploaded to a server?
No. Parser and conversion run in your browser, on your machine. Customer lists, system exports — nothing leaves your computer.