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JSON Formatter — No Upload
Pretty-print JSON without ever sending it to a server. The formatter loads once, then works entirely on your machine.
Instant
Runs entirely in your browser — no upload, no wait.
100% private
Your JSON never leaves the tab. Nothing is logged.
No signup
Free, unlimited, no account required.
Upload-free by design
Many online formatters POST your JSON to a backend, parse it server-side, and return HTML. That model is fast to build but bad for privacy. This formatter does the work in JavaScript that already runs in your tab.
What you can do without uploading
Pretty-print with configurable indentation. Minify. Validate against RFC 8259. Auto-repair common errors. Diff two payloads. Generate types. Convert between JSON, YAML, TOML, and TOON. Every feature on the site has the same upload-free guarantee.
Pasting from sensitive sources
If you are pasting JSON that contains tokens, customer PII, or internal data, the no-upload property is what your security team will ask about. The DevTools network tab is the easiest way to verify.
# Verification in 30 seconds
# 1. DevTools → Network
# 2. Clear the log, set Filter: 'Fetch/XHR'
# 3. Paste JSON, format it
# 4. Confirm zero requests appearWhat we do log
We log page views (URL only) for analytics. We do not log paste events, copy events, the JSON content, the validation result, or anything else about the data you work with.
Privacy guarantees
100% client-side processing for all JSON content. Works offline. No accounts.