About JSON Formatter
JSON Formatter & Validator pretty-prints, minifies, sorts keys, and validates JSON instantly. Errors are reported with a precise message so you can fix malformed input fast. Everything happens inside your browser — paste sensitive payloads without sending them to a server.
- No uploads
- Browser-only
- Works offline
- 100% free
How it works
- 1
Paste your JSON
Type or paste any JSON value (object, array, string, number).
- 2
Pick an action
Format with 2/4-space or tab indent, minify into a single line, or sort keys recursively.
- 3
Copy or download
Use the result in your code, copy to clipboard, or save it as a .json file.
Related tools
Browse allFrequently asked questions
Are my files uploaded to a server?
No. Every tool on SnapToolz runs entirely inside your browser using JavaScript and WebAssembly. Your file is read locally, processed in memory, and the result is offered as a download. Nothing is sent to a server — there isn't one to send to.
What kinds of JSON can I validate?
Any RFC 8259-compliant JSON. The parser is the browser's native `JSON.parse`, so trailing commas and JS-style comments will be flagged as errors (use a JSON5 tool for those).
Why use this instead of a desktop tool?
It's faster — no install, no Electron — and runs offline. The same in-browser engine validates and formats megabyte-scale payloads in a few hundred milliseconds.
What does ‘sort keys’ do?
It produces canonical JSON: every object's keys are alphabetised, recursively. Useful for diffing or signing.
Is SnapToolz free?
Yes — every tool is 100% free with no sign-up, no watermark, no hidden tier. The whole platform is open source and we have no plan to gate features.