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CSV ↔ JSON Converter

Free online tool supporting bidirectional conversion between CSV and JSON formats.

Examples

CSV Example:

name,age,city
John,30,New York
Jane,25,Los Angeles
Bob,35,Chicago

JSON Example:

[
  {"name": "John", "age": "30", "city": "New York"},
  {"name": "Jane", "age": "25", "city": "Los Angeles"},
  {"name": "Bob", "age": "35", "city": "Chicago"}
]

Key Features​

  • Bidirectional Conversion: CSV → JSON, JSON → CSV
  • Delimiter Selection: Comma, semicolon, tab, pipe
  • Header Option: Use first row as header
  • JSON Indentation: 2/4 spaces or compact
  • Swap Function: Quickly switch result to input
  • Instant Copy: Copy conversion result

What is CSV?​

CSV (Comma-Separated Values) is a text format that separates values with commas.

CSV Example​

name,age,city
John,30,New York
Jane,25,Los Angeles
Bob,35,Chicago

Characteristics​

  • Simple and lightweight
  • Easy to open in Excel
  • Suitable for spreadsheet data exchange
  • Cannot represent nested structures

What is JSON?​

JSON (JavaScript Object Notation) is a data structure in JavaScript object format.

JSON Example​

[
  {"name": "John", "age": "30", "city": "New York"},
  {"name": "Jane", "age": "25", "city": "Los Angeles"},
  {"name": "Bob", "age": "35", "city": "Chicago"}
]

Characteristics​

  • Structured data representation
  • Supports nested structures
  • Widely used in web APIs
  • Naturally integrates with JavaScript

Conversion Options​

Delimiter​

DelimiterCharacterUse Case
Comma,Most common (standard CSV)
Semicolon;European (uses comma in numbers)
Tab\tTSV files, copy/paste
Pipe``

Header Row​

With Header:

name,age,city
John,30,New York

→

[{"name": "John", "age": "30", "city": "New York"}]

Without Header:

John,30,New York

→

[["John", "30", "New York"]]

Use Cases​

1. Excel → JSON​

# Copy from Excel
Product,Price,Stock
Apple,1000,50
Banana,500,100

# Convert to JSON
[
  {"Product": "Apple", "Price": "1000", "Stock": "50"},
  {"Product": "Banana", "Price": "500", "Stock": "100"}
]

2. API Data → CSV​

# API response
[
  {"id": 1, "name": "Item A", "price": 100},
  {"id": 2, "name": "Item B", "price": 200}
]

# Export to CSV
id,name,price
1,Item A,100
2,Item B,200

3. Database Backup​

# Save SQL results as CSV
user_id,username,email
1,john_doe,john@example.com
2,jane_smith,jane@example.com

# Convert to JSON and import to NoSQL

4. Configuration File Conversion​

# config.json
{
  "settings": [
    {"key": "theme", "value": "dark"},
    {"key": "language", "value": "en"}
  ]
}

# Export to CSV
key,value
theme,dark
language,en

Programming Examples​

JavaScript​

// CSV → JSON
const csv = `name,age,city
John,30,New York
Jane,25,Los Angeles`;

const lines = csv.split('\n');
const headers = lines[0].split(',');
const result = [];

for (let i = 1; i < lines.length; i++) {
  const obj = {};
  const values = lines[i].split(',');
  headers.forEach((header, index) => {
    obj[header] = values[index];
  });
  result.push(obj);
}

console.log(JSON.stringify(result, null, 2));

// JSON → CSV
const json = [
  {name: 'John', age: 30, city: 'New York'},
  {name: 'Jane', age: 25, city: 'Los Angeles'}
];

const headers = Object.keys(json[0]);
const csv = [
  headers.join(','),
  ...json.map(row =>
    headers.map(header => row[header]).join(',')
  )
].join('\n');

console.log(csv);

Python​

import csv
import json

# CSV → JSON
with open('data.csv', 'r') as f:
    reader = csv.DictReader(f)
    data = list(reader)

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

# JSON → CSV
with open('data.json', 'r') as f:
    data = json.load(f)

with open('data.csv', 'w', newline='') as f:
    writer = csv.DictWriter(f, fieldnames=data[0].keys())
    writer.writeheader()
    writer.writerows(data)

Limitations​

CSV Limitations​

  1. Nested Structure: CSV can only represent flat data
  2. Data Types: All values treated as strings
  3. Special Characters: Requires quotes when including commas or line breaks

JSON Limitations​

  1. File Size: Larger capacity than CSV
  2. Human Readability: Low readability for complex structures
  3. Excel Compatibility: Cannot be opened directly (conversion needed)

CSV Format Considerations​

Quote Handling​

# Wrap in quotes if value contains comma
name,description
"Smith, John","Software Developer"
"Doe, Jane","Data Analyst, Manager"

Escaping​

# Double quotes inside quotes
name,quote
John,"He said ""Hello"""

Frequently Asked Questions​

Q: How are empty values in CSV handled?​

A: Converted to empty strings ("") in JSON.

Q: What about nested objects in JSON?​

A: This tool only supports flat structures. Nested objects may be converted to strings.

Q: Can it handle large files?​

A: Depends on browser memory. Use server-side tools for very large files.

Q: Can I convert Excel files directly?​

A: No. First save as CSV in Excel, then use this tool.

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Privacy​

This tool operates entirely on the client side. Your data is never sent to a server and is processed only in your browser.