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JSON Formatter & Validator

Format, validate, and beautify JSON/JSONC with key sorting, inline arrays, duplicate key detection, and rich error details—all locally.

Size: 0 BLines: 1
Input JSON
JSON Tree View
Quick Examples
Simple Object
{"name": "John", "age": 30, "city": "New York"}...
Nested Structure
{"user":{"profile":{"name":"Jane","settings":{"the...
Array of Objects
[{"id":1,"name":"Item 1","active":true},{"id":2,"n...
With Comments (JSONC)
{ // User information "name": "John", "age":...

How It Works

📋

Paste or Upload JSON Data

Input your JSON, JSONC, or JSON5 data directly into our online JSON formatter. Support for large JSON files up to 10MB. Drag and drop JSON files or paste from clipboard. Our JSON validator instantly detects syntax errors, missing quotes, and trailing commas for accurate JSON formatting.

⚙️

Configure JSON Formatting Options

Customize indentation (2, 4 spaces or tabs), enable alphabetical key sorting, remove comments from JSONC, handle special numbers (NaN, Infinity), and detect duplicate keys. Our JSON beautifier offers real-time preview with syntax highlighting and comprehensive formatting control.

✨

Validate and Format JSON Instantly

Click 'Format JSON' to beautify, validate, and fix your JSON data. Our JSON formatter processes data locally in your browser - no server uploads required. Get instant error messages with line numbers and suggestions for fixing invalid JSON syntax and structure.

💾

Export Formatted JSON Results

Download formatted JSON files, copy to clipboard with one click, or view in interactive tree mode. Export minified JSON for production, or pretty-printed JSON for debugging. Share formatted JSON via direct link or open in new window for enhanced workflow.

Problems It Solves

🔍

Problem

Debugging minified or compact JSON data becomes nearly impossible when structures are condensed into single lines, making it difficult to identify issues, understand data hierarchy, or locate specific values in API responses and configuration files.

Solution

Our JSON formatter instantly beautifies compressed JSON with proper indentation, line breaks, and visual structure. Advanced features include syntax highlighting, collapsible sections, and tree view mode for easy navigation through complex nested objects.

⚠️

Problem

Invalid JSON syntax errors are cryptic and hard to troubleshoot, especially with missing quotes, trailing commas, or incorrect nesting. Development workflows get blocked by syntax errors that are difficult to locate in large JSON files.

Solution

Comprehensive JSON validation with detailed error messages, exact line and column numbers, visual error highlighting, and helpful suggestions for fixing common JSON syntax issues. Supports JSONC with automatic comment removal.

🔄

Problem

Managing JSON data across different systems requires various formats - sometimes minified for production, sometimes formatted for development, with different key sorting requirements and encoding standards for API compatibility.

Solution

Flexible JSON processing with multiple output formats: minified for production, formatted for debugging, sorted keys for consistency, UTF-8 encoding support, and batch processing capabilities for handling multiple JSON files efficiently.

Why Choose This Tool

🔒

100% Privacy & Security

All JSON processing happens locally in your browser with zero data transmission to servers. No uploads, no logging, no data retention. Your sensitive JSON data, API responses, and configuration files remain completely private and secure.

⚡

Advanced JSON Features

Beyond basic formatting - supports JSONC comments, trailing commas, single quotes, duplicate key detection, special number handling, and interactive tree view. Perfect for modern development workflows with comprehensive JSON dialect support.

👨‍💻

Developer-Friendly Tools

Built for developers by developers. Keyboard shortcuts, auto-formatting, real-time validation, syntax highlighting, line numbers, path navigation, search functionality, and direct integration with popular development workflows.

⚡

Lightning Fast Performance

Instant processing of large JSON files up to 10MB with optimized parsing algorithms. No waiting, no timeouts, no browser crashes. Handles complex nested structures and large arrays with consistent performance across all devices.

Frequently Asked Questions

What is the difference between JSON formatting and validation?
JSON formatting makes the structure readable with proper indentation, while validation checks if the syntax follows JSON standards. This tool does both simultaneously.
Is my JSON data secure when using this tool?
Yes, all processing happens locally in your browser. No data is sent to any server or stored anywhere.
Can I format large JSON files?
Yes, but very large files (>10MB) might slow down your browser. Consider breaking them into smaller chunks if needed.
What JSON features are supported?
Standard JSON plus JSONC-style input conveniences: comments and trailing commas are safely removed. Optional support for single-quoted strings and coercion of NaN/Infinity.
Can I minify JSON as well as format it?
Yes, set the indent to 0 to create minified (compact) JSON output.
How do I pretty print JSON online?
Simply paste your JSON into the formatter and click "Format JSON". The tool will automatically pretty print your JSON with proper indentation, making it readable and well-structured.
Can I validate JSON syntax errors online?
Yes, our JSON validator automatically detects syntax errors, missing quotes, unclosed brackets, trailing commas, and other common JSON formatting issues with detailed error messages and line numbers.
How do I fix "Unexpected token" JSON errors?
Unexpected token errors usually mean missing quotes around strings, extra commas, or invalid characters. Our validator highlights the exact location and suggests fixes for these common JSON syntax problems.
Can I convert minified JSON to readable format?
Absolutely! Paste your minified (compressed) JSON and our formatter will expand it into a readable, properly indented format with clear structure and hierarchy.
Does this tool work with JSON API responses?
Yes, perfect for formatting API responses from REST APIs, GraphQL, or any web service. Copy API response JSON directly from your browser network tab or API client and format it instantly.
How do I sort JSON keys alphabetically?
Enable the "Sort keys alphabetically" option in the formatting settings. This will reorganize all object properties in alphabetical order, making JSON data easier to compare and analyze.
Can I remove comments from JSONC files?
Yes, the tool automatically removes both single-line (//) and multi-line (/* */) comments from JSONC (JSON with Comments) files, converting them to valid JSON format.
What's the maximum JSON file size supported?
The tool can handle JSON files up to 10MB efficiently. Larger files may work but could slow down your browser. For very large datasets, consider splitting them into smaller files.
How do I download formatted JSON?
After formatting your JSON, click the "Download" button to save the formatted result as a .json file, or use "Copy" to copy the formatted JSON to your clipboard for pasting elsewhere.

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