712Tools

JSON Formatter & Validator

Pretty-print, minify, and validate JSON instantly

🔒 100% in-browser🆓 Free forever⚡ No sign-up

How it works

  1. 1
    Paste your JSON

    Drop or paste any JSON string into the input box. Even messy, minified JSON works.

  2. 2
    Choose format or minify

    Pretty-print with 2 or 4 spaces, or collapse to a single line for embedding.

  3. 3
    Copy or download

    Copy formatted JSON to your clipboard or download it as a .json file.

About JSON Formatter & Validator

Free online JSON formatter, beautifier, and validator. Paste any JSON to instantly pretty-print with 2 or 4-space indentation, minify to a single line, or catch syntax errors. Runs entirely in your browser — your data never leaves your device. JSON Formatter & Validator on 712 Tools runs entirely inside your browser using modern JavaScript APIs — no server ever sees your data. That means instant results, complete privacy, and no upload limits.

Whether you need to pretty-print, minify, and validate json instantly for a debugging session, a quick sanity check, or a production incident, this tool is free to use as many times as you need. There are no watermarks, no sign-up, and no ads inside the tool itself.

Frequently asked questions

Is my JSON uploaded anywhere?

No. All parsing and formatting happens in your browser using the native JSON parser. Nothing is sent to a server.

What does the validator catch?

Missing commas, unquoted keys, trailing commas, mismatched brackets, and any invalid JSON per the RFC 8259 spec.

Can it handle large files?

Yes, up to your browser's memory limit. Files over ~50 MB may slow down the pretty-printer but validation stays fast.

Does it support JSON5 or JSONC?

Not yet. Only strict JSON (no comments, no trailing commas, keys must be double-quoted) is supported.

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