JSON (JavaScript Object Notation) is a lightweight data format. Valid JSON uses double quotes for keys and string values, comma-separated key-value pairs, and proper nesting. Minified: {'name':'John','age':30}. Formatted with 2-space indent makes it human-readable. Our formatter validates and beautifies JSON instantly.
📂 Text
📄 JSON Formatter & Validator
Format, validate, and minify JSON instantly. Paste messy JSON and get beautifully formatted output with error detection. Essential for developers, APIs, and data work.
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✨ Your Result
🦉Owl's Explanation
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Fill in the values above and click Calculate ✨
✅ Trusted Tool
The 365tool.net JSON Formatter processes all data in your browser using built-in JavaScript — nothing is ever sent to a server. Free for developers, data analysts, and API users. No sign-up needed.
🤔 How Does This Work?
The JSON Formatter uses JavaScript's built-in JSON parsing:
Format: JSON.parse() then JSON.stringify() with 2-space indentation
Minify: JSON.parse() then JSON.stringify() with no extra whitespace
Validate: JSON.parse() — if it throws an error, the JSON is invalid (shows error location)
All processing happens in your browser — no data is sent to any server.
❓ Frequently Asked Questions
What is JSON?▼
JSON (JavaScript Object Notation) is a lightweight, human-readable data interchange format. It stores data as key-value pairs using objects {} and arrays []. It is the most popular format for APIs and web services. All modern programming languages can read and write JSON.
What makes JSON invalid?▼
Common JSON errors: using single quotes instead of double quotes, trailing commas (allowed in JS but NOT in JSON), missing commas between items, unquoted keys, undefined/NaN values (not valid in JSON), comments (JSON does not support comments), and mismatched brackets.
What is the difference between JSON and JavaScript objects?▼
JSON is a text format (always a string). JavaScript objects are in-memory data structures. JSON always uses double quotes for keys. JS objects can use unquoted keys. JSON does not support undefined, functions, or comments. JSON.parse() converts JSON string to JS object. JSON.stringify() converts JS object to JSON string.
What is minified JSON?▼
Minified JSON has all unnecessary whitespace removed: newlines, spaces between tokens. This reduces file size and improves transmission speed. A formatted JSON file might be 50KB, minified version might be 20KB. APIs usually return minified JSON. Humans prefer formatted JSON for reading.
What are common JSON data types?▼
String: 'hello' (must use double quotes). Number: 42 or 3.14. Boolean: true or false. Null: null. Object: {key: value}. Array: [1, 2, 3]. JSON does not have Date, undefined, or function types — dates are usually stored as strings.
JSON (JavaScript Object Notation) is a lightweight, human-readable data interchange format. It stores data as key-value pairs using objects {} and arrays []. It is the most popular format for APIs and web services. All modern programming languages can read and write JSON.
What makes JSON invalid?▼
Common JSON errors: using single quotes instead of double quotes, trailing commas (allowed in JS but NOT in JSON), missing commas between items, unquoted keys, undefined/NaN values (not valid in JSON), comments (JSON does not support comments), and mismatched brackets.
What is the difference between JSON and JavaScript objects?▼
JSON is a text format (always a string). JavaScript objects are in-memory data structures. JSON always uses double quotes for keys. JS objects can use unquoted keys. JSON does not support undefined, functions, or comments. JSON.parse() converts JSON string to JS object. JSON.stringify() converts JS object to JSON string.
What is minified JSON?▼
Minified JSON has all unnecessary whitespace removed: newlines, spaces between tokens. This reduces file size and improves transmission speed. A formatted JSON file might be 50KB, minified version might be 20KB. APIs usually return minified JSON. Humans prefer formatted JSON for reading.
What are common JSON data types?▼
String: 'hello' (must use double quotes). Number: 42 or 3.14. Boolean: true or false. Null: null. Object: {key: value}. Array: [1, 2, 3]. JSON does not have Date, undefined, or function types — dates are usually stored as strings.