Monaco Privacy Policy

Last updated: July 5, 2026

This policy covers Monaco (monaco.yellowsunsystems.com), a Monte Carlo retirement scenario simulator operated by Yellow Sun Systems ("we," "our," or "us"). Monaco has materially different privacy properties from our other services because it runs entirely in your browser and does not require an account. For the umbrella policy covering our other services, see the Yellow Sun Systems Privacy Policy.

1. Summary

• No account, no sign-in, no email address, no name.
• Your plan is stored only in your browser's localStorage; it is never transmitted to our server.
• The server records only two aggregate counters — total page loads and total simulation runs — with no per-user attribution.
• No cookies, no analytics, no advertising trackers, no third-party scripts.
• You control your data on your device: export, import, reset, or erase, all from inside Monaco.

2. What we do not collect

When you use Monaco, we do not receive:

• Your name, email address, or any account identifier
• Your age, birthdate, or Social Security number
• Your account balances, income, expenses, or retirement plan details
• Your state of residence, Social Security claim age, or beneficiary information
• Any scenario you build, any override you apply, or any optimizer result you generate

Because Monaco never sends this information to us, there is no server-side database of user plans, no export we could produce on request, and no record we could delete for you. The equivalents of the data-subject rights described in Section 8 are performed on your device (see Section 7).

3. What the server does record

The Monaco server keeps two global aggregate counters:

• Page loads — incremented once each time the app is opened
• Simulation runs — incremented once each time you press Run Simulation

Both totals are visible in the app's About dialog. Neither counter is associated with any user identifier, IP address, session cookie, or plan content. They exist so we can see, in aggregate, whether the app is being used.

4. Your plan is stored on your device

Everything you enter in Monaco — household details, accounts, cash flows, transfers, scenarios, settings — is written to your browser's localStorage under Monaco-specific keys. This storage is:

• Local to your browser profile on this device (Chrome, Firefox, Safari, Edge, etc.)
• Not synced to any Yellow Sun Systems server
• Not encrypted at rest by the browser — see the shared-device warning in Section 6
• Persistent until you clear browser storage, use Monaco's Erase all data on this device button, or your browser clears storage on its own (e.g., after long inactivity in a private window)

5. No cookies, no analytics, no third-party scripts

• No cookies of any kind. Monaco does not set session cookies (there is no session to maintain) and does not use any tracking cookies.
• No analytics. No Google Analytics, no Segment, no Mixpanel, no first-party analytics endpoint.
• No advertising pixels. No Meta pixel, no LinkedIn Insight, no ad-network beacons.
• No third-party scripts or fonts. The Monaco page loads only assets served from Monaco's own origin.
• No fingerprinting. Monaco does not read canvas, WebGL, audio-context, or other fingerprinting surfaces to identify you.

6. Hosting and network-level logs

Monaco is hosted on Fly.io. As with any web service, Fly.io's edge infrastructure may briefly retain access logs that include your client IP address for abuse prevention and platform operations under its own policies. Monaco itself does not read, persist, correlate, or export those logs, and does not associate them with any plan content (which never leaves your browser in the first place).

7. Your controls (on your device)

Everything you can do with your Monaco data, you do inside the app:

• Export — File → Save As downloads your full plan as a portable JSON file.
• Save — File → Save writes your current plan back to the previously loaded file.
• Import — File → Open loads a JSON file you previously saved.
• Reset — File → New resets Monaco to the default plan.
• Erase — the Erase all data on this device button inside the Privacy dialog removes every Monaco key from this browser's storage, including display preferences.

8. Shared-device warning

Because your plan is stored unencrypted in your browser's local storage, anyone with access to the same browser profile on this device — or a malicious browser extension with storage-read permissions — could read it. If you are using Monaco on a shared, borrowed, or public computer, use the Erase all data on this device button before you leave, or use your browser's private / incognito mode for the session (bearing in mind that private-mode storage is cleared when you close the window, so Save As your plan first if you want to keep it).

9. Data subject rights

California residents (CCPA / CPRA). Yellow Sun Systems does not sell or share personal information for purposes of the California Consumer Privacy Act (Cal. Civ. Code § 1798.100 et seq.) as amended by the California Privacy Rights Act. Because we never receive your Monaco plan or any other personal information through Monaco, the CCPA rights to know, access, port, correct, and delete are exercised through the in-app controls described in Section 7. See Do Not Sell or Share My Personal Information for our site-wide statement.

EEA / UK residents (GDPR / UK GDPR). Yellow Sun Systems operates the Monaco marketing page and the Monaco application. Because Monaco does not receive plan content or any personal identifier, we are not a controller for the personal data you enter into Monaco — that data never leaves your device. For the two aggregate counters described in Section 3, no personal data is processed. You retain the rights of access, rectification, erasure, restriction, portability, and objection (GDPR Arts. 15–21), and the right to lodge a complaint with your local supervisory authority (GDPR Art. 77); in practice, for Monaco, the effective way to exercise these rights is through the in-app controls in Section 7.

10. Third-party AI services

Monaco does not send your plan — or any part of it — to any AI service. Simulations, optimizers, and every calculation Monaco performs run locally in your browser using code shipped with the page. There is no third-party model, no LLM prompt, and no request body that includes your plan.

11. Age requirement

Monaco is a financial-planning tool intended for adults. You must be at least 18 years old to use Monaco. The age requirement is set out in Section 5 of our Terms of Service. Because Monaco does not collect any personal information, we cannot verify age; the requirement is a contractual condition of use, not a technical control.

12. Educational-illustration disclaimer

Monaco is an educational illustration only — not investment, tax, legal, accounting, or estate-planning advice. Figures Monaco displays are modeled estimates under the assumptions you supply; real outcomes will differ. Tax tables, brackets, and state rules reflect our best understanding as of the build date and may not be current for your planning or filing year. The Find Best Plan, Max Spending, and When Can I Retire? outputs are search results under your stated objective, not recommendations. No professional client relationship is created by using Monaco. Consult a licensed professional (such as a Certified Financial Planner, Certified Public Accountant, or attorney) before acting on anything Monaco displays.

13. Changes to this policy

We may update this Monaco Privacy Policy from time to time. Material changes will be reflected in the "Last updated" date at the top of this page. Because Monaco has no account and no notification channel, we recommend checking this page occasionally if the browser-only operating model is material to your use.

14. Contact

Questions about this Monaco Privacy Policy: privacy@yellowsunsystems.com. Because we do not have your plan on our servers, please do not send plan content, balances, or account information to that address; questions about the policy itself do not require them.