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Convert CSV to JSON

Convert CSV to JSON arrays or objects, with type inference and nested key support.

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Drop your file hereor click to browseSupports CSV, TSV, or TXT files (.csv, .tsv, .txt) (Max 100MB)

**CSV to JSON conversion** is the process of transforming Comma-Separated Values data into JavaScript Object Notation, the standard data interchange format for web APIs and modern applications. CSV is a flat, plain-text format defined by RFC 4180, while JSON (ECMA-404) supports hierarchical structures with nested objects and arrays. This converter transforms each CSV row into a JSON object, with column headers becoming object keys. It uses PapaParse for RFC 4180 compliant CSV parsing and supports automatic type inference, which converts numeric strings to numbers and "true"/"false" strings to booleans. You can choose between two output formats: array of objects (the standard format for JavaScript and API consumption) or an object with column arrays (useful for charting libraries like Chart.js and D3). The converter handles edge cases like quoted fields containing commas, multi-line values, and custom delimiters. All processing runs in a Web Worker thread in your browser, keeping the interface responsive even with large datasets. The resulting JSON is valid and properly formatted, ready for direct use in JavaScript code, API payloads, or NoSQL database imports.

How to use the Convert CSV to JSON tool

  1. Load your CSV data: Drag and drop your CSV file, choose a file from your file explorer, or paste CSV data directly into the paste area.
  2. Configure output settings: Select the input delimiter, toggle header row, and enable or disable automatic type inference (converts numbers and booleans).
  3. Convert to JSON: Click the "Convert Data" button to convert each CSV row into a JSON object in an array.
  4. Export results: Copy the JSON output to your clipboard or download it as a file.

Frequently asked questions

What JSON structure does the CSV-to-JSON converter produce?
Two formats: array of objects (each CSV row becomes a JSON object with headers as keys) and columnar format (an object where each key maps to an array of column values, useful for charting). The array-of-objects format follows the JSON specification (ECMA-404) and is the standard format expected by REST APIs and JavaScript applications.
Does automatic type inference convert numbers correctly?
When enabled, numeric strings become numbers and "true"/"false" become booleans. Strings that look like numbers but should remain text (like zip codes with leading zeros) should have type inference disabled. The type inference follows JavaScript's native type coercion rules, ensuring compatibility with downstream consumers.
Can I use the output directly in a JavaScript fetch() call?
Yes. The array-of-objects format is the standard JSON format expected by REST APIs. You can pass it directly as the body of a fetch() POST request with the "application/json" content type header.
How are empty CSV cells represented in JSON?
Empty cells become empty strings ("") by default. With type inference enabled, completely empty cells become null, which is the standard JSON representation for missing values per ECMA-404.
Does the tool handle CSV with quoted fields?
Yes. PapaParse (with over 12 million weekly npm downloads) correctly handles RFC 4180 quoted fields, including fields containing commas, line breaks, and escaped double quotes. The parser is maintained by the open-source community and has been battle-tested across millions of conversions.

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