JSON to CSV Converter — Nested JSON Flattened Automatically

1Nested Object → Dot Notation Columns

[{
  "id": 1,
  "user": {
    "name": "Alice",
    "address": {
      "city": "Mumbai",
      "zip": "400001"
    }
  }
}]

id,user.name,user.address.city,user.address.zip
1,Alice,Mumbai,400001

Nested keys become column headers using dot notation: user.address.city

2Arrays of Primitives → Joined Cell

[{
  "name": "Bob",
  "tags": ["dev", "js", "api"]
}]

name,tags
Bob,"dev,js,api"

Primitive arrays are joined with commas and quoted to preserve CSV integrity.

3Inconsistent Keys → Empty Cells (No Crash)

[
  {"id": 1, "name": "Alice", "email": "a@b.com"},
  {"id": 2, "name": "Bob"}
]

id,name,email
1,Alice,a@b.com
2,Bob,

Missing keys output as empty cells — headers are always built from the full union of all keys.

PythonUsing pandas (Recommended)

import pandas as pd
import json

# From a JSON string
json_data = '[{"id":1,"name":"Alice"},{"id":2,"name":"Bob"}]'
df = pd.read_json(json_data)
df.to_csv('output.csv', index=False)

# From a JSON file
df = pd.read_json('data.json')
df.to_csv('output.csv', index=False)

# Nested JSON — use json_normalize
from pandas import json_normalize
with open('nested.json') as f:
    data = json.load(f)
df = json_normalize(data)          # flattens nested keys
df.to_csv('output.csv', index=False)

Install: pip install pandas · Works with Python 3.7+

JavaScriptVanilla JS (No Library)

function jsonToCsv(jsonArray) {
  if (!jsonArray.length) return '';
  
  // Collect all unique keys (handles inconsistent objects)
  const headers = [...new Set(jsonArray.flatMap(Object.keys))];
  
  const rows = jsonArray.map(obj =>
    headers.map(h => {
      const val = obj[h] ?? '';
      // Quote values containing commas, quotes, or newlines
      const str = typeof val === 'object' ? JSON.stringify(val) : String(val);
      return str.includes(',') || str.includes('"') || str.includes('\n')
        ? `"${str.replace(/"/g, '""')}"`
        : str;
    }).join(',')
  );
  
  return [headers.join(','), ...rows].join('\n');
}

// Usage
const data = [{"id":1,"name":"Alice"},{"id":2,"name":"Bob"}];
const csv = jsonToCsv(data);
console.log(csv);

Node.jsUsing json2csv Package

const { Parser } = require('json2csv');
const fs = require('fs');

const data = [
  { id: 1, name: 'Alice', city: 'Mumbai' },
  { id: 2, name: 'Bob',   city: 'Delhi'  }
];

const parser = new Parser();
const csv = parser.parse(data);

fs.writeFileSync('output.csv', csv);
console.log('Saved to output.csv');

Install: npm install json2csv