Local data
Bookmarks, personal notes, recent formulas, search history, theme, the last unit category, and the daily calculator tally are stored in browser local storage on the device that created them. Nothing syncs to a server.
Privacy
Private by default
The reference — formulas, constants, search, and the converter — works entirely in your browser. There are no accounts, and no data is sent to us for the core workflows.
Analytics
If analytics are enabled in production, PhysRef uses Cloudflare Web Analytics — cookieless and aggregate, with no cross-site tracking and no advertising profiles. It measures page views only, never who you are.
Payments
PhysRef Premium is optional. When you subscribe, checkout and billing are handled by RevenueCat and Stripe; your email and payment details go to them, not to us. Only an anonymous purchase id is stored in this browser so your access is recognised on this device — keep your receipt email for recovery. The whole app stays free until a payment key is configured.
Security posture
The app ships with defensive headers including a Content-Security-Policy, frame blocking, content-type protection, restricted permissions, and a strict referrer policy.