About
What Sentinel is, and how it handles your data.
What this is
Sentinel is a browser-based toolkit for password, file, and message security checks — password strength and breach checks, file integrity and metadata inspection, QR and URL safety checks, and a handful of developer-facing decoders (JWT, Base64, TOTP).
Every module runs standalone, but many are cross-linked: a URL flagged as risky links to the Unicode Inspector, a common password links to the Password Generator, and so on. You can turn these links off in Settings if you'd rather each module stood on its own.
At a glance
20
modules — all running locally
4
categories of tools
100%
runs in your browser
1
external call — HIBP breach check only
Every module
Privacy
Locally processed
All computation happens in your browser. Nothing you type, paste, or upload is sent anywhere by default.
No server
Sentinel is static files served to your browser — no backend, no account, no analytics, no telemetry.
One exception: HIBP
The breach check sends only the first 5 characters of your password's SHA-1 hash to Have I Been Pwned — a k-anonymity lookup that never transmits your actual password.
No user data collected
Nothing leaves this device for identification, syncing, or marketing.
History stays on-device
Your activity log is stored in IndexedDB, on this device only. You can clear individual entries from the Activity page, or wipe everything from Settings.