Convert CSV data to JSON format instantly. Supports custom delimiters and headers.
The CSV to JSON Converter transforms spreadsheet-style CSV data into structured JSON objects instantly in your browser, with support for comma, semicolon, tab, and pipe delimiters as well as quoted fields. It is designed for data analysts, backend developers, and automation engineers who need to move data between spreadsheet tools and JSON-based APIs or databases without writing a single line of code. Your data is processed entirely client-side and never leaves your device.
The converter splits the CSV input into rows by newline characters and then parses each row character-by-character, tracking quoted fields to correctly handle delimiters and newlines embedded inside double-quoted values. When the "First row is header" option is enabled, the first row's values become the JSON object keys and each subsequent row becomes an object with those keys. When headers are disabled, the output is an array of arrays. The final result is serialised with JSON.stringify, optionally with two-space pretty-printing.
No - the entire parsing and JSON serialisation process runs in your browser's JavaScript engine with no outbound network requests. This is particularly important for CSV files that may contain personal information such as customer names, email addresses, financial figures, or medical records. You can verify the privacy guarantee by opening your browser's Network tab in Developer Tools and confirming that no requests are sent when you click Convert.
This tool supports comma (,), semicolon (;), tab, and pipe (|) delimiters, covering the most common CSV dialects including standard RFC 4180 CSV, European locale semicolon-delimited files exported from Excel, tab-separated value (TSV) files from databases, and pipe-delimited formats used in some legacy data exchange systems. Quoted fields containing the delimiter character or embedded newlines are handled correctly. CRLF and LF line endings are both supported.
All cell values are treated as strings in the JSON output - no automatic type inference converts numeric strings to JSON numbers or "true"/"false" strings to JSON booleans. If your downstream API requires typed values, you will need to post-process the JSON output. Additionally, very large CSV files (tens of thousands of rows or files with many megabytes of data) may cause a brief pause since parsing is synchronous and blocks the browser's main thread. For bulk file processing, a server-side or command-line tool is more appropriate.
Python's csv module combined with json.dumps provides full programmatic control, type coercion, and the ability to process files of any size, while tools like csvkit or miller offer streaming and transformation capabilities for production pipelines. This browser tool has no installation requirement, works instantly in any modern browser (Chrome, Firefox, Safari, Edge), and is far faster for one-off conversions when you just need to paste some CSV and get JSON back without writing a single line of code.