CSV to JSON Converter
Transform CSV data into clean, structured JSON with full control over formatting and output style.
CSV Input
Paste CSV or drop a .csv fileJSON Output
Converted resultWhat Does This Tool Do?
The CSV to JSON Converter takes comma-separated values (or other delimited text) and transforms them into structured JSON data. Whether you are migrating data between systems, preparing API payloads, or converting spreadsheet exports for use in web applications, this tool handles the conversion entirely in your browser with no data sent to any server. It properly parses quoted fields, escaped characters, and even newlines embedded within quoted values, giving you reliable results every time.
Features
Smart Delimiter Detection
Automatically identifies whether your data uses commas, semicolons, tabs, or pipes as separators so you can paste any CSV variant without manual configuration.
Multiple Output Formats
Choose between array of objects (keyed by headers), array of arrays (raw rows), or nested grouping by the first column to match your exact data structure needs.
Automatic Type Inference
Optionally converts numeric strings like "42" and "3.14" into actual JSON numbers, and recognizes boolean and null values for cleaner output.
Drag and Drop File Support
Drop a .csv file directly onto the input panel to load its contents instantly. No need to open files separately and copy-paste their content.
Reversible Conversion
Toggle reverse mode to convert JSON back to CSV. The tool swaps panels and parsing logic so you can go both directions without switching tools.
Syntax-Highlighted Preview
The JSON output is color-coded with distinct highlights for keys, strings, numbers, and booleans, making it easy to visually verify the converted data.
How to Use
- Enter your CSV data. Paste your comma-separated text into the input panel or drag and drop a .csv file onto it.
- Configure header settings. Toggle "First row as headers" on if the first row contains column names, or off if all rows are data.
- Select your delimiter. Leave it on Auto-detect for most files, or manually choose comma, semicolon, tab, or pipe if auto-detection does not match your data.
- Choose the output format. Pick Array of objects for header-keyed records, Array of arrays for positional data, or Nested to group rows by the first column.
- Click Convert. The tool parses your CSV, displays the row and column count, and renders syntax-highlighted JSON in the output panel.
- Export your result. Use Copy to Clipboard to grab the JSON text or Download .json to save it as a file to your computer.
Example
Here is a sample CSV input and the resulting JSON output using default settings (first row as headers, array of objects, 2-space indentation):
CSV Input
name,age,city,active Alice,30,New York,true Bob,25,London,false Charlie,35,"San Francisco",true
JSON Output
[
{
"name": "Alice",
"age": 30,
"city": "New York",
"active": true
},
{
"name": "Bob",
"age": 25,
"city": "London",
"active": false
},
{
"name": "Charlie",
"age": 35,
"city": "San Francisco",
"active": true
}
]
Does this tool upload my data to a server?
No. All parsing and conversion happens entirely in your browser using JavaScript. Your data never leaves your machine, making it safe for sensitive or proprietary information.
How does the tool handle quoted fields with commas inside?
The parser follows the RFC 4180 standard for CSV. Fields enclosed in double quotes can contain commas, newlines, and escaped quotes (represented as two consecutive double quotes) without breaking the parse.
What happens if my CSV has inconsistent column counts?
Rows with fewer fields than the header will have missing columns set to null in the JSON output. Rows with more fields than expected will include the extra values. An error message is displayed to alert you about the inconsistency.
Can I convert JSON back to CSV?
Yes. Click the "Reverse: JSON to CSV" button to switch to JSON-to-CSV mode. Paste valid JSON (an array of objects or array of arrays) and the tool will produce CSV output.
What is the maximum file size supported?
Since processing is done in the browser, performance depends on your device. The tool comfortably handles files up to several megabytes. For very large datasets (50MB+), you may experience slower rendering.
How does auto-detect numbers work?
When enabled, the converter checks each cell value. If a value is a valid integer or floating-point number (like "42" or "3.14"), it is stored as a JSON number rather than a string. Toggle this off if you want all values preserved as strings.