Developer Utilities

Online JSON Formatter & Validator

Parse, Validate, and Beautify your JSON data instantly. Debug syntax errors, minify code for production, and explore complex data with our interactive Tree View.

Valid JSON|Length: 0

What is a JSON Formatter?

JSON (JavaScript Object Notation) has become the de-facto standard for data exchange on the web. From REST APIs to configuration files (like package.json), JSON is everywhere.

However, raw JSON often comes as a single, minified line of text that is impossible for humans to read. Our JSON Formatter solves this by parsing the code and organizing it into a structured, indented format (Beautification). It also validates the syntax to ensure your code is error-free.

Key Features

Instant Validation

Detects syntax errors (missing commas, brackets) in real-time and highlights the line number.

Beautify & Minify

Switch between readable (formatted) code and compact (minified) code with one click.

Tree View

Interactive visualizer allows you to collapse and expand nested objects and arrays.

Secure Processing

100% Client-side. Your sensitive API data or config files are never uploaded to the cloud.

How to Use This Tool

Cleaning up messy JSON data is effortless. Follow these steps:

1

Input Data

Paste your raw JSON code into the left editor or drag & drop a .json file.

2

Format / Validate

The tool automatically checks for errors. Click "Format" to indent the code properly.

3

Copy or Save

Copy the beautified code to your clipboard or download it as a .json file.

Understanding JSON Syntax

Common Error: In JSON, all keys (property names) must be enclosed in double quotes (e.g., "name": "John"). Single quotes are valid in JavaScript objects but cause errors in strict JSON.

Supported Data Types

  • Strings:

    Text wrapped in double quotes. Special characters must be escaped.

  • Numbers:

    Integers or floating-point numbers. No quotes needed.

  • Booleans & Null:

    true, false, or null. Written in lowercase.

  • Arrays & Objects:

    Ordered lists in square brackets [] and key-value collections in curly braces {}.

Why is my JSON invalid?

If the validator returns an error, check for these frequent mistakes:

  • Trailing Commas: {"a": 1, "b": 2,} is invalid. The last item should not have a comma.
  • Comments: Standard JSON does not support comments (// or /* */).
  • Undefined: JSON does not have an undefined type.

Frequently Asked Questions

Why does my JSON say 'Unexpected token'?▼
This usually happens due to syntax errors. Common culprits are: missing quotes around keys, using single quotes (') instead of double quotes ("), or having a trailing comma after the last item in a list.
Is my JSON data sent to your server?▼
No. This tool operates entirely client-side. Your code is processed locally in your browser using JavaScript, ensuring your sensitive data (like API keys or config details) never leaves your computer.
What is the difference between JSON and XML?▼
JSON (JavaScript Object Notation) is lighter, easier to read, and faster to parse than XML. It uses key-value pairs and arrays, whereas XML uses a tag-based structure similar to HTML.
Can I format large JSON files?▼
Yes, but it depends on your browser's memory. Since we process files locally, you can typically handle files up to 50MB-100MB without issues. Extremely large files may cause the browser to lag.
What does 'Minify' do?▼
Minification removes all unnecessary whitespace, newlines, and indentation from the JSON code. This reduces the file size, making it ideal for data transmission over networks.

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