JSON Formatter & Validator

Paste your JSON to format, beautify, minify & validate — with syntax highlighting, line numbers and instant error reporting. Free, no login required.

Input — Raw JSON

Output — Formatted

Formatted output will appear here...

About JSON — JavaScript Object Notation

JSON (JavaScript Object Notation) is a lightweight, text-based data interchange format that is easy for humans to read and write, and easy for machines to parse and generate. It was derived from JavaScript but is language-independent and supported by virtually every modern programming language.

JSON is the most widely used format for APIs, configuration files, and data storage in web and mobile applications. It has largely replaced XML for data interchange on the web due to its simplicity and smaller payload sizes.

JSON Syntax Rules

JSON has a small set of strict syntax rules:

Data is written as key-value pairs, with keys always in double quotes.
Values can be strings, numbers, booleans (true/false), null, arrays, or objects.
Strings must use double quotes — single quotes are not valid JSON.
No trailing commas are allowed after the last item in an array or object.
No comments are permitted in standard JSON.

Example JSON

{ "name": "DoAide", "version": 2, "features": ["format", "validate", "minify"], "pricing": { "plan": "free", "loginRequired": false } }

JSON vs XML

JSON has become the preferred format over XML for web APIs for several reasons: it is more concise (no closing tags), faster to parse, and maps directly to native data structures in JavaScript and most languages. XML retains advantages in document markup, namespaces, and schema validation for enterprise systems, but for typical API communication, JSON is the standard choice.

Common JSON Use Cases

REST APIs: Nearly all modern web APIs use JSON for request and response bodies.
Configuration files: Tools like package.json, tsconfig.json, and VS Code settings use JSON.
Data exchange: JSON is used to transfer data between client and server, between microservices, and for data import/export.
NoSQL databases: MongoDB, CouchDB, and Firebase store data in JSON-like formats.
Logging: Structured logging with JSON makes logs machine-parseable and searchable.

Why Use a JSON Formatter?

Raw or minified JSON is difficult to read. A JSON formatter adds indentation and line breaks to make the structure clear. This tool also validates your JSON syntax and highlights errors with their exact location, helping you debug API responses, configuration files, and data payloads quickly.

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. It is the standard format for web APIs.

What does a JSON formatter do?

A JSON formatter takes raw or minified JSON and adds proper indentation (usually 2 spaces) and line breaks to make it human-readable. It can also validate JSON syntax and report the exact location of errors.

Is my data safe?

Yes. All processing happens entirely in your browser using JavaScript. Your JSON data is never sent to any server. You can even use this tool offline once the page is loaded.

Is this tool free to use?

Yes, this JSON formatter and validator is completely free. No login or signup is required.

Can I format large JSON files?

This tool handles JSON up to several megabytes comfortably in modern browsers. For very large files (50MB+), a desktop tool like jq may be more appropriate.