100% Client-side · Your JSON never leaves your browser
Format & Beautify JSON Online
Pretty-print messy JSON instantly with 2 or 4-space indentation. Live as you type. Works offline.
JSON Tools
Choose your method.
Beautify — pretty-print with 2-space indentation. Cmd+Enter to run
Input 0 chars
Output
Mode
Indent
Paste JSON and it updates live.
Or press Cmd+Enter.
FAQ
JSON Formatter — Frequently Asked Questions
Everything you might wonder about our online JSON formatter and JSON beautifier.
Is this JSON formatter free to use?
Yes — the online JSON formatter is 100% free, with no signup, no rate limits and no ads. Paste any JSON payload and get pretty-printed, valid JSON instantly.
Does the JSON formatter send my data to a server?
No. Formatting happens in your browser via the native JSON.parse / JSON.stringify. We have no servers, no logs of your data, and no behavioural analytics on your JSON — your data never leaves your machine.
How big a JSON payload can the formatter handle?
Hundreds of KB beautify in milliseconds. Multi-MB payloads format fine on modern hardware — the limit is your browser, not us.
Can I choose 2-space or 4-space indentation?
Yes — toggle the indent control above the output panel to switch between 2-space and 4-space JSON pretty-print. Tabs are not currently supported (file an issue if you need them).
Does the JSON beautifier preserve key order?
Yes. We use the native JSON parser which keeps insertion order, so your beautified output mirrors the input structure key-by-key.
Can the JSON formatter fix invalid JSON automatically?
Yes — switch to Auto-Fix mode to repair trailing commas, single-quoted strings, unquoted object keys, and JS/JSONC comments. For pure validation without edits, use the JSON Validator.
Does this JSON formatter work offline?
Yes. After the first page load all assets are cached, so the JSON formatter works offline in any modern browser — perfect for air-gapped or restricted networks.
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