Best JSON Formatter & Validator Online

Free No signup · No data stored · Works offline Trusted by 500K+ developers
Indent
Error
Single quotes auto-converted to double quotes
INPUT
OUTPUT
// output here

More Developer Tools

JSON→YAML
To YAML config
JSON→CSV
Array to CSV
JSON→XML
To XML markup
JSON→TOML
To TOML config
YAML Formatter
Format & validate
XML Formatter
Format & validate
Base64
Encode / Decode
JWT Decoder
Inspect tokens

Why This Is the Best JSON Formatter & Validator

Format & Beautify JSON

Paste minified or unformatted JSON and instantly get a clean, indented, human-readable result. Choose 2-space, 4-space, or tab indentation.

Validate & Detect Errors

Real-time JSON validation with precise error messages. Pinpoint syntax mistakes instantly and auto-fix common issues like single quotes.

Tree View & Minify

Explore nested JSON in an interactive collapsible tree. Minify JSON for production to reduce payload size. Download results as a .json file.

Privacy First

All processing runs entirely in your browser. No data is ever sent to a server. Safe for sensitive or confidential JSON data.

Frequently Asked Questions

What is a JSON Formatter?

A JSON formatter takes raw or minified JSON text and reformats it with consistent indentation and line breaks, making it easy to read and debug. It also validates whether the JSON is syntactically correct.

Is it safe to paste sensitive JSON data here?

Yes. This tool processes all JSON entirely in your browser using JavaScript. No data is transmitted to any server, making it safe for API keys, tokens, and private data.

How do I fix a JSON parse error?

Click "Validate" to see the exact error location. Common issues include single quotes instead of double quotes (use "Fix Quotes"), trailing commas, or missing brackets. The error message shows the exact position of the problem.

Can I format large JSON files?

Yes. You can upload .json or .txt files directly using the upload button. The formatter handles large files efficiently in-browser without any size limit imposed by a server.

In-depth guide
The Complete JSON Guide
Format, validate, convert & best practices
Read the guide