What is JSON?
JSON (JavaScript Object Notation) is the most widely used data format for exchanging information between servers and web applications. It is lightweight, human-readable, and supported by every modern programming language.
You encounter JSON every day as a developer:
- •API responses from REST and GraphQL endpoints
- •Configuration files like
package.json and tsconfig.json
- •Database records in NoSQL databases like MongoDB
- •Local storage data in web browsers
- •Webhook payloads from services like Stripe and GitHub
The Problem with Unformatted JSON
When JSON comes back from an API or gets minified for production, it looks like this:
``
json
{"user":{"id":1,"name":"John Doe","email":"john@example.com","role":"admin","active":true},"posts":[{"id":101,"title":"Hello World","published":true},{"id":102,"title":"Second Post","published":false}]}
`
That is impossible to read or debug. A formatted version looks like this:
`
json
{
"user": {
"id": 1,
"name": "John Doe",
"email": "john@example.com",
"role": "admin",
"active": true
},
"posts": [
{
"id": 101,
"title": "Hello World",
"published": true
},
{
"id": 102,
"title": "Second Post",
"published": false
}
]
}
`
Much easier to read, debug, and understand.
How to Format JSON Online (Step by Step)
Step 1 — Open the JSON Formatter
Go to our free JSON Formatter. No login, no installation required.
Step 2 — Paste Your JSON
Copy your raw or minified JSON and paste it into the input area. This works with any valid JSON — objects, arrays, nested structures, or large API responses.
Step 3 — Format and Validate
Click Format. The tool will:
- •Beautify your JSON with proper indentation
- •Validate the syntax and highlight any errors
- •Show line numbers for easy navigation
- •Highlight keys, values, strings and numbers in different colors
Step 4 — Copy the Result
Click Copy to copy your formatted JSON to clipboard with one click.
Common JSON Errors and How to Fix Them
| Unexpected token | Missing comma or bracket | Check for missing , between items |
| Unexpected end | Incomplete JSON | Make sure all brackets are closed |
| Invalid string | Unescaped quotes | Replace " inside strings with \" |
| Trailing comma | Extra comma at end | Remove the last comma before } or ] |
JSON vs JavaScript Object
A common mistake is confusing JSON with a JavaScript object. They look similar but have key differences:
- •JSON keys must be in double quotes —
"name"
not name
- •JSON does not support comments
undefined
values
- •JSON does not support functions
How to Get JSON in Different Languages
`
javascript
// JavaScript — parse JSON string
const data = JSON.parse(jsonString);
// JavaScript — convert object to JSON
const json = JSON.stringify(data, null, 2);
`
`
python
Python — parse JSON
import json
data = json.loads(json_string)
Python — convert to JSON
json_output = json.dumps(data, indent=2)
`
`
php
// PHP — parse JSON
$data = json_decode($json_string, true);
// PHP — convert to JSON
$json = json_encode($data, JSON_PRETTY_PRINT);
``
Is My JSON Data Safe?
Yes. All formatting and validation happens entirely in your browser using JavaScript. Your JSON data never leaves your device and is never sent to any server.
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