CSV to JSON Converter
Convert between CSV and JSON, both directions, in your browser.
How it works
CSV looks trivial and is not. A field may contain the delimiter, a line break, or a quotation mark, and the escaping rules — double the quote inside a quoted field — are what separates a parser that works from one that silently corrupts a row. This one implements RFC 4180 properly, so a value like <code>"Smith, John"</code> stays a single field and an embedded newline does not split a record.
Type detection converts anything that round-trips through a number back to a number, and true/false to booleans. It deliberately leaves values with leading zeros alone: a postcode of 01234 or an ID like 007 must stay text, and a converter that turns them into 1234 and 7 has destroyed the data.
Common questions
Does my data get uploaded?
No. Parsing and serialising both happen in your browser. Nothing is sent anywhere, which matters when the spreadsheet has customers in it.
Why are my leading zeros preserved?
Because they are almost always significant — postcodes, account numbers, part codes. Anything with a leading zero is kept as text. Switch type detection off if you want every field to stay a string.
What happens to nested JSON?
CSV is flat, so nested objects and arrays are serialised into their cell as JSON text rather than being silently flattened or dropped.