JSON Formatter

Format, beautify, and validate JSON data instantly with syntax highlighting and error detection.

✓ Valid JSON
Lines: Size:

How It Works

Paste your raw or minified JSON into the input area and click Format. The tool parses your JSON using the browser's built-in JSON parser, checks for syntax errors, and outputs a properly indented, human-readable version.

JSON (JavaScript Object Notation) is a lightweight data interchange format widely used in APIs, configuration files, and web applications. When JSON is minified or generated programmatically, it becomes hard to read. Our free JSON Formatter tool instantly converts compact JSON into a clean, indented, human-readable format.

**What is JSON Formatting?**

JSON formatting — also called JSON beautifying or JSON pretty-printing — adds proper indentation and line breaks to a JSON string, making nested objects and arrays easy to read and debug. For example, minified JSON like `{"name":"John","age":30}` becomes properly indented with each key on its own line.

**JSON Validation**

Beyond formatting, this tool also validates your JSON. If your JSON contains a syntax error — a missing comma, an unclosed bracket, or an invalid value — the tool pinpoints exactly where the error occurs. This is invaluable when debugging API responses or configuration files.

**When to Use a JSON Formatter**

- Debugging API responses from REST or GraphQL endpoints
- Reading configuration files in JSON format
- Reviewing JSON data from databases or log files
- Preparing JSON for documentation or sharing with team members
- Learning JSON structure by examining real-world examples

**JSON Formatting Rules**

Valid JSON must follow strict rules: strings must be quoted with double quotes, numbers can be integers or decimals, boolean values are `true` or `false` (lowercase), and `null` represents an empty value. Arrays are enclosed in `[]` and objects in `{}`.

**JSON vs JavaScript Objects**

JSON is stricter than JavaScript object notation. JSON requires all keys to be double-quoted strings. JavaScript objects can use unquoted keys. Functions, comments, and `undefined` values are not allowed in JSON.

**Practical Use Cases**

Developers encounter JSON constantly — REST API responses, GraphQL data, localStorage values, package.json, tsconfig.json, and more. Having a reliable formatter eliminates eye strain from reading minified JSON during debugging sessions.

**Privacy**

All JSON processing happens entirely in your browser using JavaScript. Your data is never sent to our servers, ensuring complete privacy for sensitive API responses or configuration data.

Frequently Asked Questions

JSON (JavaScript Object Notation) is a text-based data format used to exchange information between applications. It stores data as key-value pairs and supports strings, numbers, booleans, arrays, and objects.
Yes. All JSON processing happens entirely in your browser using JavaScript. Your data is never sent to our servers.
Common JSON errors include: trailing commas after the last item, single quotes instead of double quotes, missing quotes around keys, and undefined or function values (not supported in JSON).
JSON is a text format derived from JavaScript syntax, but it is stricter. JSON requires double-quoted keys and string values, and does not support functions, comments, or undefined values.
Yes, but very large JSON files (over 1MB) may cause the browser to slow down. For files larger than 5MB, consider using a desktop tool like VS Code.