JSON Formatter & Validator

Format, validate, and explore JSON data — fast, private, and entirely in your browser

Input
Paste or type JSON in the input panel to get started
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What is JSON?

JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format that has become the standard for data communication on the web. Originally derived from JavaScript, JSON is now language-independent and supported by virtually every modern programming language, framework, and platform.

JSON structures data using two universal constructs: objects (collections of key-value pairs enclosed in curly braces) and arrays (ordered lists of values enclosed in square brackets). Values can be strings, numbers, booleans (true/false), null, or nested objects and arrays — making JSON both simple and expressive enough for complex data models.

Whether you are building REST APIs, configuring applications, storing documents in NoSQL databases, or exchanging data between microservices, JSON is the format you will encounter most often. Tools like this formatter help ensure your JSON is valid, readable, and ready for use.

How to Use This Tool

  1. Enter your JSON — Paste JSON directly into the input panel, drag and drop a .json file, upload a file using the Upload button, or load data from a URL.
  2. Real-time validation — As you type, the tool automatically validates your JSON. The status bar at the bottom shows whether your JSON is valid, along with detailed error messages pointing to the exact line and column of any issues.
  3. Format or minify — Click Format to beautify your JSON with your preferred indentation (2 spaces, 4 spaces, or tabs). Click Minify to compress it into a single line for transmission or storage.
  4. Explore with Tree View — Switch to the Tree View tab to navigate your JSON data as an expandable, collapsible tree. Each node shows its type and value, making it easy to understand deeply nested structures.
  5. Check Statistics — Switch to the Statistics tab to see a breakdown of your JSON: total size, maximum nesting depth, number of keys, and a count of each data type used.
  6. Copy or download — Use the copy or download buttons in the output panel header to save your formatted or minified result.

Features

JSON Validation
Instantly validate your JSON with precise error messages. Errors are highlighted directly in the editor with line and column numbers, so you can fix issues fast.
Format & Beautify
Transform messy, minified, or unreadable JSON into clean, properly indented output. Choose your preferred indentation style and optionally sort keys alphabetically.
Minify & Compact
Strip all unnecessary whitespace to produce the smallest possible JSON output. Ideal for reducing payload size in API responses and configuration storage.
Tree View
Visualize your JSON as an interactive, expandable tree. Navigate complex nested structures with ease — each node shows its data type and value at a glance.
Statistics
Get a complete overview of your JSON data: file size, maximum nesting depth, total key and value counts, and a breakdown by data type (strings, numbers, booleans, etc.).
100% Client-Side
Your data never leaves your browser. All formatting, validation, and analysis happen locally using JavaScript — no data is sent to any server, ever. Your JSON stays private.

JSON Syntax Quick Reference

Type Example Description
String "hello world" Unicode text enclosed in double quotes. Supports escape sequences like \n, \t, \".
Number 42, 3.14, -1e10 Integer or floating-point. No leading zeros, no hex/octal. Supports scientific notation.
Boolean true, false Lowercase only. No quotes — "true" is a string, not a boolean.
Null null Represents an intentionally empty value. Lowercase only.
Object {"key": "value"} Unordered collection of key-value pairs. Keys must be double-quoted strings.
Array [1, "two", true] Ordered list of values. Values can be any type, including nested objects and arrays.

Frequently Asked Questions

What is JSON?
JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format. It is easy for humans to read and write, and easy for machines to parse and generate. JSON is widely used in web APIs, configuration files, and data storage across virtually every programming language.
Is my JSON data safe when using this tool?
Yes. All JSON processing happens entirely in your browser using JavaScript. Your data is never sent to any server. There is no backend — this is a completely static website hosted on Cloudflare Pages. Your data stays on your device.
What is the maximum JSON file size this tool can handle?
There is no hard limit, but for optimal performance, we recommend files under 2 MB. For files over 500 KB, real-time validation is automatically disabled to keep the interface responsive — you can still click Format or Minify to process larger files.
What does JSON formatting do?
JSON formatting (also called beautifying or pretty-printing) adds consistent indentation and line breaks to make JSON data human-readable. This tool lets you choose between 2 spaces, 4 spaces, or tab indentation, and optionally sort object keys alphabetically.
What is JSON minification?
JSON minification removes all unnecessary whitespace (spaces, tabs, line breaks) from JSON data, producing the smallest possible representation. This is useful for reducing file size when transmitting JSON data over a network or storing it efficiently.
Can I use this tool offline?
Since all processing happens in your browser, once the page is loaded, the formatting and validation features work without an internet connection. However, the Load from URL feature requires an active internet connection to fetch external data.
What keyboard shortcuts are available?
Press Ctrl+Enter (or Cmd+Enter on Mac) to format the current JSON input. All standard text editing shortcuts work in the input area, including undo, redo, select all, and find.
Why does "Load from URL" sometimes fail?
Most web servers implement CORS (Cross-Origin Resource Sharing) policies that prevent other websites from directly fetching their data. If a URL is blocked by CORS, you can copy the JSON content from the source and paste it into the input panel instead.