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.