JSON Formatter & Validator

Online JSON Formatter

Paste JSON to instantly prettify, validate, or minify it. Works entirely in your browser — nothing is uploaded or stored.

Open the Tool — Free & Instant

Your data never leaves your browser

No server processing

All diffing runs locally in your browser using JavaScript. Zero data transmitted.

No logging or storage

We do not store, log, or read your content. Nothing is saved anywhere.

Safe for sensitive content

Confidential code, config files, API keys — safe to compare here.

PII detection on share

Before any share link is generated, your content is scanned for emails, API keys, and tokens — with options to redact or encrypt.

Features

✓Pretty-print JSON with 2-space indentation
✓Minify JSON to a single compact line
✓Validates JSON and shows exact parse errors
✓Copy formatted output with one click
✓100% in-browser — JSON never sent to a server
✓Works with nested objects, arrays, and minified JSON
✓No account or sign-up required
✓Free forever

Frequently Asked Questions

How do I format JSON online?

Paste your JSON into the input box above and click "Format". The tool will pretty-print it with 2-space indentation. If the JSON is invalid, you'll see an exact error message.

What is the difference between pretty-print and minify?

Pretty-print adds indentation and newlines to make JSON human-readable. Minify removes all whitespace to produce the smallest possible JSON string — useful for APIs and storage.

Can I validate JSON without formatting it?

Yes. Paste your JSON and click Format — if it's invalid, the error message tells you exactly what's wrong and where. If it formats successfully, your JSON is valid.

Is my JSON data kept private?

Completely. All formatting runs in JavaScript locally in your browser. Nothing is sent to any server. Safe to use with API responses, config files, and sensitive data.

Can I compare two JSON files after formatting?

Yes. Use the JSON Diff tool to compare two JSON files key-by-key. You can also paste formatted JSON into the main diff tool for a line-by-line comparison.