JSON Formatter Online Free — Format, Validate, Fix & Convert JSON

JSON is everywhere — APIs return it, config files use it, databases store it. But raw JSON is often a single unreadable line or worse, broken with syntax errors. This guide shows you exactly how to format, validate, fix, and convert JSON online for free — with real examples for every step.

What is a JSON Formatter?

A JSON formatter takes raw or minified JSON and adds proper indentation and line breaks to make it human-readable. It also validates the syntax and highlights errors. A good formatter should also be able to fix common mistakes automatically.

For example, this is minified JSON from an API response:

{"user":{"id":1,"name":"John Doe","email":"[email protected]","roles":["admin","editor"],"active":true,"created":"2026-01-15"}}

After formatting:

{
  "user": {
    "id": 1,
    "name": "John Doe",
    "email": "[email protected]",
    "roles": [
      "admin",
      "editor"
    ],
    "active": true,
    "created": "2026-01-15"
  }
}

How to Format JSON Online — Step by Step

How to Validate JSON Online

Validation checks if your JSON is syntactically correct. Even a single missing comma or extra bracket will make JSON invalid and break your API.

Example of invalid JSON and what the validator catches:

{
  "name": "John",
  "age": 25,          // trailing comma
  "city": 'Dubai'     // single quotes not allowed
  "active": True      // Python literal, not valid JSON
}

How to Fix Broken JSON Automatically

The Fix & Analyze button is the most powerful feature. It automatically repairs the most common JSON errors in one click — no manual editing needed.

What it fixes automatically:

• Single quotes → double quotes
• Unquoted keys → properly quoted keys
• Python literals → True → true, False → false, None → null
• Trailing commas after last array/object items
• Missing commas between items

What it flags for your review (data warnings):

• Inconsistent types in arrays (e.g. id is number in row 1, string in row 2)
• Numeric strings that should be numbers (e.g. "price": "49.99")
• Reversed date ranges (end_date before start_date)

Try it with this broken JSON:

{
  'company': "TechCorp",
  founded: 2018,
  active: True,
  score: "42",
  tags: ["dev", "python",],
}

Fixed 4 issues:
✓ Converted 2 single quotes to double quotes
✓ Added quotes around 3 unquoted keys
✓ Converted 1 Python literal (True → true)
✓ Removed 1 trailing comma

Data warning:
⚠ "score" is a String ("42") but looks like a Number

How to Fix JSON Using Schema (Schema Fix)

Schema Fix is the most powerful feature for developers working with APIs. If your JSON has the right structure but wrong data types, Schema Fix reads your JSON Schema and corrects every value automatically.

Example — your API is returning strings instead of numbers:

{
  "id": "1042",
  "price": "29.99",
  "in_stock": "yes",
  "category": 5
}

{
  "properties": {
    "id": { "type": "number" },
    "price": { "type": "number" },
    "in_stock": { "type": "boolean" },
    "category": { "type": "string" }
  }
}

{
  "id": 1042,
  "price": 29.99,
  "in_stock": true,
  "category": "5"
}

How to Convert JSON to CSV Online

CSV is useful when you want to open JSON data in Excel, Google Sheets, or import into a database. JSON to CSV conversion works when your JSON is an array of flat objects.

[
  {"name": "John", "age": 30, "city": "Dubai"},
  {"name": "Jane", "age": 25, "city": "Doha"},
  {"name": "Bob",  "age": 35, "city": "London"}
]

name,age,city
John,30,Dubai
Jane,25,Doha
Bob,35,London

How to Convert JSON to YAML Online

YAML is widely used in DevOps config files, Kubernetes manifests, GitHub Actions, and Docker Compose. Converting JSON to YAML makes config files much more readable.

{
  "service": "api",
  "replicas": 3,
  "ports": [8080, 8443],
  "env": {"NODE_ENV": "production"}
}

service: api
replicas: 3
ports:
  - 8080
  - 8443
env:
  NODE_ENV: production

How to Convert JSON to XML Online

XML is still widely used in enterprise systems, SOAP APIs, and configuration files. Converting JSON to XML is straightforward.

{"name": "John", "age": 30, "city": "Dubai"}

<?xml version="1.0" encoding="UTF-8"?>
<root><name>John</name><age>30</age><city>Dubai</city></root>

How to Use JSON Path to Query JSON

JSON Path lets you extract specific values from complex nested JSON — like querying a database but for JSON. It is essential when working with large API responses.

Common JSON Path examples:

{
  "store": {
    "products": [
      {"name": "Laptop", "price": 999},
      {"name": "Phone",  "price": 499},
      {"name": "Tablet", "price": 299}
    ]
  }
}

Path: $.store.products[*].price → returns [999, 499, 299]

Path: $.store.products[0].name → returns "Laptop"

JSON Formatter Features Comparison

Common JSON Errors and How to Fix Them

1. Single quotes instead of double quotes

{'name': 'John'}

{"name": "John"}

2. Trailing comma after last item

{"tags": ["dev", "api",]}

{"tags": ["dev", "api"]}

3. Unquoted keys

{name: "John", age: 25}

{"name": "John", "age": 25}

4. Python literals

{"active": True, "deleted": False, "data": None}

{"active": true, "deleted": false, "data": null}

5. Comments in JSON

{
  // This is a user object
  "name": "John"
}

{"name": "John"}

Frequently Asked Questions