CSV ↔ JSON Converter

CSV to JSON Conversion Guide

CSV (Comma-Separated Values) and JSON (JavaScript Object Notation) are the two most common data interchange formats. This tool converts between them instantly in your browser — no data leaves your machine.

How CSV to JSON Works

When converting CSV to JSON, the first row is treated as headers (keys), and each subsequent row becomes a JSON object:

// CSV
name,age,city
John,32,NYC

// JSON
[
  { "name": "John", "age": "32", "city": "NYC" }
]

Handling Edge Cases

• Quoted fields: Fields with commas are wrapped in quotes: "New York, NY"
• Escaped quotes: Double quotes inside quoted fields: "He said ""hello"""
• Newlines in fields: Quoted fields can contain newlines
• Empty values: Converted to empty strings in JSON
• Numbers: Auto-detected and converted to JSON numbers when possible

Code Examples

// JavaScript — CSV to JSON
function csvToJson(csv) {
  const lines = csv.split('\n');
  const headers = lines[0].split(',');
  return lines.slice(1).map(line => {
    const values = line.split(',');
    return Object.fromEntries(
      headers.map((h, i) => [h.trim(), values[i]?.trim()])
    );
  });
}

// Python
import csv, json
with open('data.csv') as f:
    data = list(csv.DictReader(f))
    print(json.dumps(data, indent=2))

When to Use CSV vs JSON

• CSV: Tabular data, spreadsheets, database exports, data analysis
• JSON: APIs, web applications, nested/hierarchical data, config files