JSON Formatter & Validator

Free online tool to format and validate JSON.

Input (JSON)

Sort KeysIndent:

Result

How to Use

1. Paste JSON or text into the input field
2. Select desired action (Format, Minify, or Validate)
3. Click the corresponding button to convert
4. Click 'Copy' to copy or 'Download' to save as file

What is JSON?

JSON (JavaScript Object Notation) is a lightweight 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.

Key Features

Format: JSON Formatting - Pretty print JSON for readability
Minify: JSON Minify - Remove unnecessary whitespace to reduce file size
Validate: JSON Validation - Check if JSON is valid
Sort Keys: Sort Keys - Sort JSON keys in alphabetical order
Indent: Indent Control - Choose indentation (2, 4, 8 spaces, etc.)
Download - Save result as JSON file

JSON Formatter Tips

Format API response data to easily understand data structure.
Minify large JSON files to reduce network transmission size.
Use sort keys to standardize JSON objects for easier CI/CD comparison.
Use validation to quickly find and fix invalid JSON.

※ Notice

All data processed here is handled only in your browser - nothing is stored on servers.
JSON validation follows RFC 7159 standard
Very large JSON files (100MB+) may cause browser performance issues
Korean characters and special characters are handled correctly

Frequently Asked Questions

JSON (JavaScript Object Notation) is a lightweight text format for storing and transmitting data. It is easy for humans to read and write, and easy for machines to parse. It is used as a standard data exchange format in web API responses, configuration files, database storage, and many other fields.

API responses or compressed JSON appear as a single line without spaces or line breaks, making them hard to read. Formatting adds indentation and line breaks so you can understand the data structure at a glance. This makes debugging and data inspection much faster and easier during development.

JSON validation checks whether the input text follows the JSON standard specification (RFC 7159). It inspects double quote usage, comma placement, bracket pairing, and other rules to determine if the format is parseable. If there are errors, it displays a specific error message indicating where the problem occurred.

Choose the number of indentation spaces based on code readability and your team's conventions. Generally, 2 spaces is popular in web development while 4 spaces is preferred in some language conventions. If file size matters, use the minify option to remove all whitespace.

A Complete Guide to JSON Format

JSON Data Types and Structure

JSON supports six data types: string, number, boolean, null, array, and object. Objects are represented with curly braces and arrays with square brackets, with data organized as key-value pairs. Through nested structures, even complex data models can be expressed, making JSON the core data format of modern web development.

Using JSON Formatter as a Development Tool

A JSON formatter is an essential tool for various development tasks including API development, debugging, and data analysis. Formatting REST API responses lets you quickly understand the response structure and find the fields you need. Using the sort keys feature makes it easier to compare multiple JSON files or track changes in a version control system.

JSON Optimization and Performance

In production environments, JSON minification removes unnecessary whitespace to reduce data transmission size. Minification typically reduces file size by 10-30%, improving network performance. A good practice is to use formatted JSON for readability in development environments and switch to the minified version for deployment.

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