The short version: nothing you type into D Fetcher leaves your browser to our servers. The long version follows.
Nothing. The calculator runs entirely in your browser. Inputs you type — location, skin type, exposed body area, age, target dose — are saved only in your browser's localStorage under the key dfetcher.settings.v1 so they persist between visits. They are never transmitted to D Fetcher.
The calculator makes three categories of outbound request, all directly from your browser to the upstream service:
These services see the latitude/longitude you compute against, the user agent your browser sends, and your IP address as part of any normal HTTP request. D Fetcher does not proxy these calls; we have no record of them.
The "Use my location" button asks your browser for your coordinates via the standard Geolocation API. Your browser will prompt you for permission. If you grant it, the coordinates are written to the lat/lon inputs and stored in localStorage with the rest of your settings. They are not transmitted to D Fetcher.
No cookies. No analytics. No trackers, fingerprinting, or advertising scripts.
The JSON API at /api/calculate and the MCP server at /mcp are stateless Cloudflare Pages Functions. They receive the parameters you pass, make the same upstream calls described above, and return the computed result. We log only what Cloudflare logs by default for any HTTP request (IP, user agent, URL, timestamp) for operational purposes; we do not retain query content or build user profiles.
To wipe your locally-stored settings, click Advanced → Clear saved settings on the calculator page. Or clear site data for dfetcher.com in your browser's settings.
If we ever change what we collect or where we send it, we'll update this page and add an entry to the changelog.