CSV ↔ JSON Converter

CSV / JSON Converter

Paste or upload your data below. Switch between CSV → JSON and JSON → CSV modes. Customize delimiters, quote handling, and output format using the options bar.

What is CSV and When Do You Convert?

CSV (Comma-Separated Values) is a plain-text format where each line is a data record and each field is separated by a delimiter — usually a comma. JSON (JavaScript Object Notation) is a structured key-value format used by APIs and web applications. You typically need to convert between these formats when: importing/exporting data from spreadsheets (Excel, Google Sheets) into a web API, transforming API responses for use in data analysis tools, or migrating data between different software systems.

How to Use the CSV ↔ JSON Converter

1. Choose CSV → JSON or JSON → CSV mode using the tabs above.
2. Paste your data into the input box, or drag and drop a .csv or .json file.
3. Set your options: delimiter character, quote character, whether the first row is a header, and whether to auto-detect data types.
4. Click Convert to see the output with syntax highlighting.
5. Switch to Table Preview to visualize your data as a formatted table.
6. Copy the output, download it as a file, or click Use as Input to round-trip the conversion.

Key Features

• CSV → JSON: Converts delimited text to an array of objects (using the header row as keys) or a 2D array.
• JSON → CSV: Flattens an array of JSON objects into CSV rows with auto-generated headers.
• Custom delimiters: Comma, semicolon, tab, pipe, or any custom character.
• Auto-type detection: Converts numeric strings to numbers and true/false to booleans automatically.
• Table preview: Visualize the converted data as a scrollable, formatted table.
• File upload: Drag and drop .csv, .tsv, or .json files.
• Syntax-highlighted JSON output with pretty-print or minified toggle.
• Download output as .json or .csv file.
• 100% browser-based: Your data never leaves your device.

CSV Format Tips

• Fields containing the delimiter character must be wrapped in the quote character (e.g. "New York, NY").
• To include a quote character inside a quoted field, double it: "He said ""hello""".
• Empty fields are represented as two consecutive delimiters: Alice,,London.
• Line endings can be \n (Unix), \r\n (Windows), or \r (old Mac) — this tool handles all three.
• TSV (Tab-Separated Values) files work by selecting the Tab delimiter option.