Converting CSV to JSON and back
CSV is the lowest common denominator of data: every spreadsheet, database and analytics tool can export it. JSON is what web APIs, JavaScript code and most configuration systems expect. Moving data between the two by hand means fighting quotes, commas inside values and header rows.
This converter turns CSV into a JSON array and JSON back into CSV, following the quoting rules of RFC 4180. With headers on, each row becomes an object keyed by the column names.
How to use it
- Choose CSV → JSON or JSON → CSV.
- Set the delimiter: comma by default, or a semicolon or tab for exports from European spreadsheets and databases.
- Keep With headers on when the first CSV row holds column names; switch it off to get plain arrays of values.
- Paste the data, then copy the output or download it as a file.
Example: quotes and commas inside values
name,city,note "Doe, Jane",New York,"said ""hi""" Ada,London,
[
{
"name": "Doe, Jane",
"city": "New York",
"note": "said \"hi\""
},
{
"name": "Ada",
"city": "London",
"note": ""
}
]The quoted field keeps its comma, the doubled quotes become one quote character, and the empty last field becomes an empty string.
The CSV quoting rules
RFC 4180 is the closest thing CSV has to a standard. A field that contains the delimiter, a double quote or a line break must be wrapped in double quotes, and a double quote inside such a field is written twice. Everything else is plain text. When converting JSON to CSV, this tool adds the quotes only where they are needed.
Spreadsheets in countries that use a comma as the decimal separator, such as Germany or France, usually export CSV with semicolons. If every row lands in a single column, the delimiter is the problem.
Everything is text
CSV has no data types, so the numbers 42 and 007 arrive in JSON as the strings "42" and "007". That is deliberate: guessing would turn postal codes, phone numbers and IDs with leading zeros into wrong numbers. Convert the columns you need in your own code, where you know what each one means.
JSON shapes that convert well
JSON to CSV expects an array of flat objects with the same keys, like the output above. The column headers come from the keys. Nested objects or arrays have no natural place in a flat table; flatten them first, for example by turning address.city into its own key.
Questions
Will Excel open the CSV correctly?
Usually. If accented characters look wrong, import the file through Excel's Data menu and choose UTF-8, since double-clicking may assume an older encoding.
Is there a size limit?
Files of a few megabytes convert instantly. Everything happens in browser memory, so very large exports can slow the page down.
Is my data uploaded?
No. Parsing and conversion run in your browser, which makes it safe for customer lists and exports.