Last updated October 14, 2026
The short version
We collect as little as possible and never sell your data.
Deal numbers
The calculator runs entirely in your browser. The prices, rents and expenses you type are not sent to our servers unless you are a Pro member and choose Save deal; saved deals are stored privately with our hosting provider (Vercel) and you can delete them anytime.
Sign-in
Pro sign-in uses a one-time code emailed to you and a secure session cookie. We do not use passwords.
Email address
If you join the newsletter or buy Pro, we store your email (and name, if given at checkout) with our email provider, Resend, to send the newsletter and member updates. Every email includes an unsubscribe link.
Payments
Payments are handled by Stripe. We never see or store your full card number. Stripe's privacy policy applies to the payment information you give them.
Hosting and logs
The site is hosted on Vercel, which may keep standard technical logs (like IP address and browser type) for security and reliability. We don't use advertising trackers.
Your choices
To see, correct or delete your data, email support@usefirstdoor.com.