Yes. Formatting happens entirely in your browser using JavaScript. We never see or store your JSON data.

How does the validation work?

The engine checks your input on every keystroke. If there's a syntax error, like a missing comma or quote, it calculates the exact line and column and shows you a clear error message.

What is the Tree View feature?

Tree View shows large, nested JSON as a folder-like structure you can expand or collapse, which makes it much easier to navigate a big data set.

Can I format JSON using tabs instead of spaces?

Yes. You can choose between 2 spaces, 4 spaces, or tabs for the output.

JSON Formatter & Validator - Free Online Tool

How to Format JSON

Paste your minified or messy JSON into the editor and click Format. It'll indent everything using whichever spacing you prefer: 2 spaces, 4 spaces, or tabs. Toggle Tree View when you're working with a deeply nested object and want to expand only the parts you care about, or hit Minify if you need to shrink it back down. Any syntax error shows up right away, with the exact line and column where it broke.

Why Use This JSON Formatter Tool?

JSON is the standard format for moving data between servers and web apps, but APIs almost always return it minified as one long line that's nearly impossible to read. That's the gap this tool fills. Instead of a plain textarea that just runs JSON.stringify, it's built on CodeMirror, so you get real syntax highlighting and a validation engine that catches a missing comma or a stray bracket the moment you type it, pointing straight to the line and column where things went wrong. For anyone working with large payloads, the Tree View turns a wall of text into something you can actually navigate: expand only the nodes you need instead of scrolling forever. And because everything runs client-side, you can format API keys or other sensitive data without worrying about it touching a server.

Key Features

✓CodeMirror Editor: Syntax highlighting, line numbers, and auto-bracket matching, similar to what you'd get in VS Code.
✓Interactive Tree View: Expand and collapse nested objects and arrays like folders, which makes debugging a large API response a lot less painful.
✓Flexible Indentation: Switch between 2 spaces, 4 spaces, or tabs to match your project's style.
✓Instant Validation: The tool checks your JSON as you type and points to the exact line and column of any error.
✓One-Click Minification: Strip out whitespace and line breaks when you need a compact file for deployment or transfer.
✓Runs Locally: Parsing and formatting all happen in your browser, so nothing gets uploaded.

JSON Formatter