CSV to JSON
Convert CSV (comma, semicolon or tab separated) into clean JSON, with header detection. Free and fully in-browser.
[
{
"name": "toolko, inc",
"role": "builder",
"free": "true"
},
{
"name": "say \"hi\"",
"role": "greeter",
"free": "false"
}
]How to use the CSV to JSON
- 1Paste your CSV text into the input box, or upload a .csv file using the file picker.
- 2Choose the delimiter, comma, semicolon or tab, or leave it on auto-detect to let the tool infer it from your data.
- 3Toggle 'First row is header' on to produce an array of objects keyed by your column names, or off to get an array of arrays.
- 4Click Convert and review the formatted JSON that appears in the output panel.
- 5Copy the JSON to your clipboard with the Copy button, or download it as a .json file.
- 6If numbers or fields look merged, switch the delimiter setting and convert again to correct the parsing.
About the CSV to JSON
CSV to JSON turns tabular data into structured JSON entirely inside your browser, so nothing you paste ever leaves your computer. It reads three common delimiters, comma, semicolon and tab, which covers the vast majority of exports. Semicolon files are especially common in regions where the comma is used as a decimal separator, and many European Excel installs default to them, so the tool auto-detects the delimiter rather than forcing you to guess. When header detection is on, the first row becomes the object keys and every following row becomes one object in an array, giving you the clean array-of-objects shape that most APIs, config files and JavaScript code expect. Turn header detection off and you get an array of arrays instead, useful when your CSV has no header line.
Technically, the conversion happens through JavaScript running on the page. There is no upload, no server round trip and no request logged anywhere, which makes it safe for spreadsheets that contain customer emails, order data or internal figures you would never send to an unknown web service. Parsing respects quoted fields, so a value like "Doe, John" stays a single field instead of splitting on the comma inside it, and quoted line breaks inside a cell are preserved.
Real use cases are everywhere. Front-end developers seed a mock API or a local database from a spreadsheet a client sent. QA engineers convert test fixtures. Marketers reshape a CRM export before pushing it into a tool that only accepts JSON. Students and analysts move data from Excel into a notebook or a JavaScript chart. Anyone wiring up a no-code automation that expects JSON payloads can paste a CSV and get the exact structure needed.
Practical tips: keep your header names short and free of stray spaces so the resulting keys are easy to reference in code, check that the detected delimiter matches your file if numbers look merged, and use the array-of-objects output when feeding REST endpoints. Because everything is local, large files convert instantly and work offline once the page has loaded.
Frequently asked questions
How does the tool handle commas that appear inside a field value?
Fields wrapped in double quotes are treated as a single value, so "Doe, John" stays intact instead of being split into two columns. The parser only breaks on delimiters that fall outside of quotes, which matches the standard CSV quoting rules.
My file uses semicolons instead of commas. Will it still work?
Yes. Semicolon-separated files, which are common in European Excel exports where commas are decimal separators, are fully supported. Leave the tool on auto-detect or manually pick semicolon as the delimiter.
What is the difference between header detection on and off?
With header detection on, the first row supplies the keys and each remaining row becomes an object, giving an array of objects. With it off, no row is treated specially and you get an array of arrays, which is what you want for headerless CSV files.
Are number and boolean values converted to real JSON types?
By default CSV values are text, so the safest behaviour is to output them as strings. If you need typed numbers or booleans, convert the resulting JSON in your code, since automatic type coercion can misread things like leading-zero IDs or postal codes.
Is my data uploaded anywhere when I convert it?
No. The entire conversion runs in your browser using JavaScript, so the CSV never touches a server and no copy is stored or transmitted. You can even use it offline once the page has loaded, which makes it safe for confidential spreadsheets.
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Frequently asked questions
Which delimiters work?+
Comma, semicolon and tab — the first row is used as keys.