JSON Formatter & Validator

About the JSON Formatter & Validator

JSON is everywhere — API responses, config files, log lines, exports — and it's unforgiving about a single misplaced comma. This tool takes messy, minified, or broken JSON and makes it readable in an instant: it pretty-prints with the indentation you choose, validates against the JSON spec, and tells you exactly where a problem is by line and column. Switch to the tree view to fold large structures down to the parts you care about.

It all runs in your browser. Your JSON is never uploaded, never logged, and never sent anywhere — which matters, because that payload you're debugging might contain API keys, tokens, or customer data you'd rather not paste into a random website.

What it does

• Format & beautify. Pretty-print with 2 spaces, 4 spaces, or tabs, with syntax highlighting that makes structure obvious at a glance.
• Validate with pinpoint errors. Invalid JSON gets a clear message plus the exact line and column, with the offending line shown and a caret under the problem.
• Minify. Collapse to the smallest valid one-line form for shipping in code or saving bytes.
• Interactive tree view. Explore nested objects and arrays, collapse the noise, and see key counts and array lengths at every level.
• Sort keys. Alphabetize object keys recursively to make two payloads easy to compare.
• Copy or download the result, and load a .json file straight from disk.

Common uses

• Make an unreadable, minified API response human-readable while debugging.
• Find the exact comma or bracket breaking a config file before it breaks your build.
• Minify a JSON blob to paste into source code or a query string.
• Inspect a deeply nested structure without scrolling through thousands of lines.
• Normalize key order so a diff between two payloads shows only real changes.

Good to know

• Validation follows strict JSON (RFC 8259): double-quoted keys and strings, no trailing commas, no comments. If your text is really a JavaScript object literal, those are the usual culprits the error message will point at.
• Everything is computed locally with your browser's native JSON engine, so it's fast and private. Extremely large documents are bounded only by your device's memory.

No account, no upload, no nonsense — paste, read, fix, ship.

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