Free CSV to JSON Converter

CSV (Comma-Separated Values) is a plain-text tabular format where each row is a record and columns are separated by a delimiter (usually a comma). JSON (JavaScript Object Notation) is a hierarchical key-value format that supports nested structures, arrays, and typed values (numbers, booleans, null). CSV is compact and easy to open in spreadsheets like Excel or Google Sheets; JSON is richer and widely used in APIs, web applications, and data pipelines.

When data type detection is enabled, the converter inspects each cell value: strings that parse as finite numbers become JSON numbers (e.g. '123' → 123, '3.14' → 3.14); 'true' and 'false' (case-insensitive) become JSON booleans; empty strings and the literal string 'null' become JSON null. Everything else remains a string. Disable the toggle to keep all values as strings.

Yes. The parser fully implements RFC 4180: fields containing the delimiter, double-quotes, or newlines must be enclosed in double-quotes. For example: John,"Smith, Jr.",30 correctly parses as three fields. Literal double-quotes inside a quoted field are escaped by doubling them: "He said ""hello""" becomes He said "hello". This works for any supported delimiter.

NDJSON (Newline-Delimited JSON) outputs one JSON object per line with no enclosing array. It is ideal for streaming large datasets, log ingestion pipelines (Elasticsearch, Splunk, Logstash), and tools that process records line by line — like jq, Python’s json.loads in a loop, or AWS Kinesis. Standard JSON Array output is better for REST APIs, JavaScript applications, and small to medium datasets.

The converter uses chunked processing: rows are parsed in batches using setTimeout to yield the browser event loop and avoid UI freezing. A progress bar shows parsing status. Only the first 200 rows are rendered in the syntax-highlighted panel; the full dataset is included when you download the .json file. For very large files (50MB+), consider splitting them first, as browser memory limits may apply.