Convert CSV to JSON in your browser: RFC 4180 quoting, auto delimiter detection, header-row option. Files never leave your device. No upload — runs 100% in your browser
CSV is the export format of every system ever built; JSON is the input format of every API and script written since. This page bridges them locally: paste CSV, get JSON — with the header row mapped to object keys and each data row becoming one object.
The parser follows RFC 4180, the actual CSV specification: fields wrapped in double quotes may contain commas and line breaks, a literal double quote inside a quoted field is written twice (""), and a UTF-8 BOM at the start of the file is stripped. Those three details are exactly where naive split(',') converters produce corrupted data — the sample above deliberately includes a quoted comma and a quoted thousands separator.
Auto-detect inspects the first line (outside quotes) and picks comma, semicolon, tab or pipe — semicolon matters because several European locales export CSV with it. The header option switches between an array of objects (first row = keys) and a plain array of arrays. Empty or duplicate column names are made unique automatically.
Values are kept exactly as written. A ZIP code 0755 or an ID 00123 survives intact, which automatic number-typing would destroy. If your consumer needs numbers, convert in your script where the schema is known.
No. Everything on this page runs inside your browser using JavaScript and WebAssembly. Your file never leaves your device — you can even disconnect from the internet after the page loads and the tool still works.
Deliberately: automatic number conversion destroys leading zeros (ZIP codes, account IDs) and regionally formatted numbers. Keep them as strings, or convert where the schema is known.
Yes — RFC 4180 quoting is fully implemented, including escaped quotes and CRLF line endings.
The practical limit is your browser's memory; files of several MB paste and convert in a moment. For truly huge CSVs use a scripted solution.