How to Convert CSV to JSON: A Developer's Guide

CSV vs JSON: Format Comparison

Here's the same data in both formats:

name,age,city
Alice,28,Jakarta
Bob,34,Surabaya
Carol,22,Bandung

[
  {"name":"Alice","age":28,"city":"Jakarta"},
  {"name":"Bob","age":34,"city":"Surabaya"},
  {"name":"Carol","age":22,"city":"Bandung"}
]

Method 1: Online Tool (Quickest)

Use our CSV to JSON converter to paste or upload a CSV and get formatted JSON output instantly — with options to control key names, data types, and output structure.

1. Open the CSV to JSON tool
2. Paste your CSV or upload a .csv file
3. The first row is used as field names by default
4. Click Convert and copy or download the JSON output

Method 2: JavaScript

function csvToJson(csv) {
  const lines = csv.trim().split('\n');
  const headers = lines[0].split(',').map(h => h.trim());
  return lines.slice(1).map(line => {
    const values = line.split(',');
    return headers.reduce((obj, header, i) => {
      obj[header] = values[i]?.trim() ?? '';
      return obj;
    }, {});
  });
}

const csv = `name,age,city
Alice,28,Jakarta
Bob,34,Surabaya`;

console.log(JSON.stringify(csvToJson(csv), null, 2));

For production use, prefer a library like Papa Parse — it handles quoted fields, escaped commas, different line endings, and streaming large files.

Method 3: Python

import csv
import json

with open('data.csv', newline='', encoding='utf-8') as f:
    reader = csv.DictReader(f)
    data = list(reader)

with open('data.json', 'w', encoding='utf-8') as f:
    json.dump(data, f, indent=2)

print(f"Converted {len(data)} rows")

Python's built-in csv.DictReader uses the header row as dictionary keys automatically — no third-party libraries required.

Handling Common Edge Cases