Last updated: March 22, 2026
This policy describes how Winterfat LLC, doing business as Winterfat Diagnostics (“Winterfat,” “we,” “us”) handles data at winterfat.xyz.
Our free tools (CWC Calculator, Fuel Optimizer, CNA Renewal Checker) do their work in your browser. Where we can avoid sending your inputs to a server, we do. What you type into a calculator is yours.
We do not sell, rent, or trade your data to third parties. Full stop.
Data we do collect is used to operate our services and to improve our tools for customers. If a calculation is producing bad results, we want to know. If a tool is confusing to use, we want to fix it. We use aggregate, anonymized usage patterns to make Winterfat better for the people who depend on it.
Account and service data is stored in Supabase, which provides encrypted storage with role-based access controls. Audit and assessment data is backed up on zero-knowledge, encrypted storage.
Winterfat does not request access to your camera, microphone, or location. Our website makes it impossible for any code on our site to do so.
We use a small number of third-party services to operate: Supabase (database), Clerk (authentication), Resend (email delivery), and Flowglad (payments, built on Stripe). Each handles your data under their own privacy policies. We do not give them more than they need to do their job.
Questions? Contact us.