Free Online JSON Formatter & Validator

Quickly format, beautify, validate, and minify your JSON data with our free online tool. Perfect for developers, QA engineers, and anyone working with JSON APIs. No signup, no data stored on servers — everything runs in your browser.

Features

JSON Formatter & Beautifier — Pretty-print JSON with configurable indentation (2 spaces, 4 spaces, or tabs)
JSON Validator — Instantly detect syntax errors with precise line numbers and descriptions
JSON Minifier — Compress JSON by removing all unnecessary whitespace
Interactive Tree View — Explore JSON structure with collapsible/expandable nodes
Syntax Highlighting — Color-coded keys, strings, numbers, booleans, and null values
Line Numbers — Easy reference for large JSON documents
Dark & Light Theme — Toggle between themes for comfortable editing
Drag & Drop Upload — Load .json files by dragging onto the editor or using the file picker
One-Click Copy — Copy formatted or minified output to your clipboard

How to Use

Paste your JSON into the input panel on the left, or drag & drop a .json file
Click Format to beautify, Minify to compress, or Validate to check for errors
Switch to Tree view to explore nested structures interactively
Click Copy to copy the output to your clipboard

Frequently Asked Questions

Is my JSON data safe?

Yes. All processing happens entirely in your browser. No data is sent to any server. Your JSON never leaves your machine.

What JSON errors can this tool detect?

The validator catches all syntax errors including missing commas, unmatched brackets, invalid string escapes, trailing commas, single-quoted strings, and more. Error messages include the approximate line number and a plain-English description.

Can I format large JSON files?

Yes. The formatter handles files up to several megabytes directly in the browser. For extremely large files (50MB+), consider using a command-line tool like jq.

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 the most common format for web APIs and configuration files.