CSV to JSON Converter
Paste CSV or open a file to get clean JSON — an array of objects or arrays — with proper handling of quotes, line breaks, delimiters and data types. Large files up to 10 MB+ work too.
Runs in your browser — nothing is uploaded Free, no limits
Options
CSV input
JSON output
Output appears here.How to use the CSV to JSON
- Paste your CSV or click Open file (.csv, .tsv or .txt).
- Check the options: delimiter (auto-detected), header row, number/boolean conversion, output shape and indent.
- Review the preview table and any line-numbered warnings, such as rows with missing fields.
- Copy the JSON or download it as a .json file.
Frequently asked questions
How are quotes and commas inside values handled?
The converter follows RFC 4180: a field wrapped in double quotes may contain commas, line breaks and quotes, where a quote is written twice (""). So "Hopper, Grace" stays one value.
My CSV uses semicolons — will it work?
Yes. The delimiter is detected automatically from the first lines (comma, semicolon, tab or pipe), and you can override it. Excel in many European locales saves CSV with semicolons.
Why are some numbers kept as strings?
With type conversion on, values like 42 or 3.14 become numbers, but values with leading zeros (ZIP codes like 01234) and integers too large for JavaScript (over 9,007,199,254,740,991) stay strings so no digits are lost.
What happens with rows that have too few or too many fields?
They are still converted and listed as warnings with their line number. Missing fields are left out of that object and extra fields get column_N names, so you can spot and fix broken rows.
Can I create nested JSON from CSV?
Yes. Turn on “Nest dot headers” and columns like address.city and address.zip become { "address": { "city": …, "zip": … } }.
Is my data uploaded?
No. Parsing runs entirely in your browser, so even large or confidential files never leave your device.