Privacy Policy

Last updated: June 16, 2026

fyrslf (“fyrslf,” “we,” “us”) is operated by an individual based in Colorado, USA. This policy explains what information we collect, how we use it, and the choices you have. We’ve tried to keep it plain-spoken. If anything is unclear, email us at support@f0x.cc.

Information we collect

The numbers you enter. Ages, balances, contributions, assumptions, and similar inputs you type into the calculator. If you use the tool without signing in, these are stored only in your own browser.
Account information. If you choose to sign in, our authentication provider (Google Firebase) processes your email address and, for Google sign-in, basic profile details. We use this to identify your account and sync your saved scenarios.
Saved scenarios.When you sign in and save a scenario, your inputs are stored in our database (Google Firestore) so they’re available across your devices.
Sharing details.If you share a scenario, we use the recipient’s email address to deliver the invitation and store the sharing relationship between accounts.
Technical data. Like most websites, our hosting and infrastructure providers automatically receive standard technical information (such as IP address, browser type, and basic performance metrics) needed to operate and secure the service.

How we use your information

To provide the calculator and save and sync your scenarios.
To send scenario-sharing invitations you request.
To send service-related email (for example, sharing notifications), which you can control through your email-notification preference in your profile.
To operate, secure, maintain, and improve fyrslf.

Service providers

We rely on third-party providers to run fyrslf, including Google Firebase and Firestore (authentication and data storage) and Resend (email delivery). These providers process data on our behalf and handle it under their own privacy and security practices.

Advertising

fyrslf does not currently display advertising. We may introduce ads in the future. If and when we do, advertising or analytics partners may collect information through cookies or similar technologies, and we will update this policy to describe that use before it takes effect.

Your choices and rights

Know what we have. You can ask us to disclose the categories and specific pieces of personal information we hold about you, the sources, and why we collect it. The export described below includes this summary, and you can email us for anything more.
Access and download your data. From your profile you can download a copy of your account data — a complete JSON file (with a summary of the categories we hold) and a CSV of your scenarios. Some records can only be retrieved on our end (your full sign-in history, invitations you’ve already accepted, and email-delivery logs); to request the complete record, email support@f0x.cc and we’ll verify your request and respond.
Delete your data. You can delete individual saved scenarios at any time from within the app, and you can delete your profile and account from your profile settings.
Email preferences. You can turn sharing notifications on or off from your profile.
Use without an account. You can use the calculator without signing in, in which case your inputs stay in your browser.

Data retention

We keep your account and saved scenarios for as long as your account is active. When you delete a scenario or your account, we remove the associated data from our database, though residual copies may persist briefly in backups before being overwritten.

Children

fyrslf is intended for adults. The service is not directed to anyone under 18, and we do not knowingly collect personal information from people under 18.

Changes to this policy

We may update this policy from time to time. When we do, we’ll revise the “Last updated” date above, and material changes will be reflected here.

Contact

Questions about this policy? Email support@f0x.cc.