JSON Formatter & Validator
Format, validate, minify and explore JSON.
JSON Formatter pretty-prints JSON with the indentation you choose, validates it with a precise error location when it is broken, minifies it back down, and gives you a collapsible tree view for exploring large documents. Parsing happens in your browser, so API payloads with real data stay private.
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Runs entirely on your device. No file or text you enter here is uploaded. How to verify it.
How to use JSON Formatter & Validator
- Paste your JSON, or open a .json file.
- Format, minify, or switch to the tree view.
- Copy or download the result.
Questions about JSON Formatter & Validator
What does the error message tell me?
The line and column of the failure plus the surrounding text, and a plain explanation of the likely cause — a trailing comma, a single quote, an unquoted key, or an unescaped control character. These four account for most invalid JSON.
Can it handle very large files?
Documents of a few megabytes are fine. The tree view renders lazily, so only the nodes you expand are built. Beyond roughly 50 MB, browser memory becomes the limit and you will feel it.
Does it support JSONC or trailing commas?
There is a lenient mode that accepts comments and trailing commas and repairs them into valid JSON, clearly marked so you know the input was not strictly valid.
Does it work offline?
Yes, once the page has loaded. Parsing and formatting are done by JavaScript already in your tab, so a dropped connection changes nothing. Installed as a web app, it opens with no network at all.
Is it safe to paste a payload containing customer data?
The JSON is parsed in your own tab and never sent anywhere — the browser network panel will show you that. Treat your clipboard and browser history as part of the picture too, since a payload with a live token is still a live token.
Is JSON Formatter & Validator really free, with no limits?
Yes. There is no account, no daily cap, no file-size tier and no watermark, because there is no server cost to recover. The site is funded by clearly disclosed partner recommendations on the Partners page, never by metering the tools.
Are my files or text uploaded when I use JSON Formatter & Validator?
No. Everything is processed by JavaScript running in your browser, on your device. You can verify it: open your browser's developer tools, switch to the Network tab, and use the tool. You will see no request carrying your data — because there is nowhere for it to go.