SafeJSON — The JSON tool that never sees your data

A privacy-first JSON formatter. Format, validate, and debug JSON entirely in your browser. No server. No ads. No tracking.

Why SafeJSON?

In November 2025, popular online JSON tools were caught leaking over 80,000 credentials — AWS keys, GitHub tokens, and banking details. Around the same time, the most popular JSON Formatter browser extension (2M+ users) was sold, closed-sourced, and injected with adware.

SafeJSON is different: all processing happens in your browser. Zero network requests.

Features

Web Tool (safejson.vercel.app)

• Instant JSON formatting with syntax highlighting
• Collapsible tree view for exploring nested structures
• Error detection with line and column numbers
• Copy / Download formatted JSON
• Dark theme by default
• Cmd+Enter to format

Browser Extension

• Auto-detects JSON responses on any URL
• Syntax highlighting: strings (green), numbers (gold), booleans (cyan), null (gray)
• One-click Copy / Raw toggle
• "Open in SafeJSON" button for full tree view inspection
• Available on Edge Add-ons

How to verify the privacy claim

1. Open safejson.vercel.app
2. Open DevTools → Network tab
3. Paste any JSON
4. Observe: zero network requests

All formatting runs client-side. Your data never leaves your browser.

Install the extension

From Edge Add-ons Store

Search "SafeJSON" in the Edge Add-ons store.

Manual install (Chrome / Edge / Brave)

1. Download or clone this repository
2. Open chrome://extensions (or edge://extensions)
3. Enable "Developer mode"
4. Click "Load unpacked"
5. Select the extension/ folder

Tech stack

• Next.js 16
• Tailwind CSS
• Phosphor Icons
• Deployed on Vercel

How SafeJSON compares to other JSON tools

Feature	SafeJSON	jsonformatter.org	codebeautify.org
Client-side processing	Yes	No — server-side	No — server-side
Data leaves your device	Never	Yes	Yes
Open source	Yes (MIT)	No	No
Ads	None	Yes	Yes
Data breach history	None	80K+ credentials leaked (Nov 2025)	Same breach
JSON Diff	Yes (Pro)	No	No
JWT Decoder	Yes (Pro)	No	No
JSONPath	Yes (Pro)	No	No
Schema Validator	Yes (Pro)	No	No
Price	Free (core), $5/mo (Pro)	Free (ad-supported)	Free (ad-supported)

Competitive context

jsonformatter.org and codebeautify.org were found by security researchers at watchTowr (November 2025) to have leaked over 80,000 user credentials — including AWS keys, GitHub tokens, and banking details — through an unprotected "Recent Links" feature. The data was accessible without authentication, and attackers were confirmed to be actively scraping the data within 48 hours.

SafeJSON was built in response: if all processing happens in the browser, there is nothing to leak.

License

MIT