CSV to JSON Converter
Paste your CSV below and get JSON instantly. The conversion happens entirely on your device — nothing is uploaded — so it's safe for private data and works offline once loaded.
Example: CSV → JSON
CSV in
name,role
Ada,Engineer
Grace,Admiral
JSON out
[
{
"name": "Ada",
"role": "Engineer"
},
{
"name": "Grace",
"role": "Admiral"
}
]How it works
The converter parses your CSV into an in-memory data structure, then serialises that structure as JSON. Because both steps run client-side in JavaScript, conversion is instant and your data never touches a network. The same engine powers every JSON / YAML / XML / CSV pairing, so results stay consistent across directions — you can round-trip CSV → JSON and back without surprises.
Tips for clean JSON
- Use the From / To selectors to switch formats, or the ⇄ button to reverse the conversion and reuse the output as input.
- Set the indent to match your project's style (2 or 4 spaces).
- Invalid input shows a clear error message pointing at the problem instead of failing silently.
Good to know
This CSV to JSON Converter turns tabular data — the kind you export from spreadsheets, databases, or analytics dashboards — into a JSON array of objects right inside your browser. It treats the first row as the column headers and maps every following row into an object keyed by those headers, so a file with name,role becomes a list of {"name": ..., "role": ...} records. It's built for developers, data analysts, and anyone who needs to feed spreadsheet-style data into an API, a config file, or a front-end app without writing a parser.
Re for it when you have a CSV from Excel, Google Sheets, or a database dump and the next step expects JSON — seeding a mock API, loading fixtures into a test, populating a JavaScript array, or pasting into a tool that only accepts JSON. Because it runs locally and uploads nothing, it's a safe choice for data you can't paste into a random web service, such as internal exports or anything with personal information.
Read the output as an ordered array: each element corresponds to one CSV data row, in the original order, and every object shares the same keys drawn from the header. The converter is type-aware, so a cell containing 42 comes out as the number 42 (no quotes), true/false become booleans, and empty or null-looking cells become JSON null. If a value stays wrapped in quotes in the output, that means it was kept as a string.
A few practical notes that affect your results:
- Quote any field that itself contains a comma, otherwise it will be split into two columns — proper CSV quoting (
"Smith, John") is parsed correctly. - Watch out for unintended type coercion: a ZIP code like
02118 or a phone number may lose its leading zero or become a number; force it to stay text by quoting it or adjusting the source. Use the indent setting and the reverse (⇄) button to round-trip back to CSV and confirm nothing changed.
Frequently asked questions
Does it use the first row as keys?
Yes. The first CSV row is treated as the header, and every following row becomes a JSON object keyed by those column names.
Are numbers and booleans detected?
Yes — values that look like numbers, true/false or null are converted to the matching JSON type. Quoted commas inside a field are parsed correctly.
Is my data uploaded anywhere?
No. The conversion runs entirely in your browser using JavaScript — your data never leaves your device and nothing is sent to a server.
Is this converter free?
Yes, completely free with no sign-up, and no limits. It even works offline once the page has loaded.
People also ask
What does CSV to JSON output look like?
It produces a JSON array where each item is an object representing one CSV row. The object keys come from the header row, so all objects share the same property names in the order the columns appear.
How are empty CSV cells handled in the JSON?
An empty cell typically becomes an empty string or null depending on how the value is interpreted. Cells that look like the literal word null are converted to JSON null rather than the text "null".
Can I convert JSON back to CSV?
Yes. Use the From/To selectors or the reverse (⇄) button to flip the direction, which reuses the output as input so you can round-trip CSV to JSON and back to CSV.
Does the converter handle commas inside a field?
Yes, as long as the field is wrapped in double quotes following standard CSV rules. A value like "Paris, France" is treated as a single field instead of being split into two columns.
Will leading zeros in numbers like ZIP codes be preserved?
Values that look numeric may be converted to JSON numbers, which can drop leading zeros. To keep them as text, ensure they are quoted in the source CSV or treat the column as a string before converting.
Does this work with tab-separated or semicolon-delimited files?
This tool is built for comma-separated values. Files using tabs or semicolons as the delimiter may not split into columns correctly unless they are first converted to standard comma delimiters.
Is there a size limit on the CSV I can convert?
There is no server-imposed limit because the conversion runs entirely in your browser. Very large files are bounded only by your device's available memory and browser performance.
What's the difference between an array of objects and nested JSON?
This converter outputs a flat array of objects, with one object per row and one key per column. It does not infer nested structures from the CSV, so dotted or hierarchical column names are kept as plain string keys.
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