Privacy
Last updated 22 September 2026
ZetaInvest is a set of free calculators. This page says exactly what is kept, why, for how long, and how to get rid of it. It is written to be read rather than to be complied with.
The short version. You can use every tool without an account, and if you do, nothing about you is stored — the figures you type never leave your browser. An account exists so a vote can be one person rather than one browser. It holds an email address, a name, a password nobody can read, and a few preferences you choose.
Who is responsible
ZetaInvest is run by one person, not a company. The calculators are free and always will be. One thing here involves money: an optional tip (“buy me a coffee”), taken by Stripe on Stripe’s own pages. It is not required to use anything on this site, it is not handled on this site, and see “Where it goes” for who processes what. Questions, requests and complaints: hello@zetamethod.com.
What is held, and why
| Email address | It is how you sign in, and how we tell you a tool shipped if you asked us to. |
| Name | To address you in an email. Nothing else reads it. |
| Password | Stored as an argon2id hash. It cannot be read or reversed, by us or by anyone who took a copy of the database. |
| Country, currency, language | So the tools deflate by the right inflation and read in the right money. Guessed from your connection, and correctable by you. |
| Year of birth (optional) | Only to understand who the tools reach. Never asked for, never required, and blank for anyone who skips it. |
| Where you are with investing (optional) | To know what the audience looks like, and eventually to decide how much a tool explains by default. |
| Your vote | To count it. Kept after a round closes, with your country and currency copied alongside it, so past rounds can be analysed. |
| Tool suggestions | To read them and build the thing. |
| Whether you want email | Off unless you say otherwise, and reversible from any email or from your account. |
| Sign-in attempts, by address | To rate-limit sign-in, so nobody can spend your address on a flood of codes. Holds your address and a count of attempts for the window it fell in, and nothing else. Deleted within three hours. |
| IP address | To rate-limit sign-in, registration and the tip button, so one machine cannot flood them. Held the same way as the row above — a count against the address for one clock hour — and never attached to your account or to anything you did. Deleted within three hours. |
| Session records | To keep you signed in. Deleted when you sign out, and when you set a password. |
What is never held
The numbers you put into the calculators. The monthly investing, retirement and rent-or-buy tools compute in your browser, against price history the site already sent you. Your spending, your salary, your savings and your target are never transmitted anywhere and never stored, including when you are signed in. That is a property of how they are built, not a promise about how we behave.
The emergency fund tool is the exception, because it reads what you write. The description you type is sent to an AI model so it can work out which questions it does not need to ask you. We do not store that description. What the model works out from it, whether your pay is steady, who depends on it, roughly what share goes to housing, is kept only if you press “attach these answers to my account”, and is deleted with your account. The monthly figure you type is treated the same way. The one exception is the country, if you are asked where you live and answer: that is saved to your profile, because it is what the currency and the tax assumptions are read from.
While that tool is open, your answers are also held in your browser’s own storage for the tab, so that reloading the page does not lose the result you just worked for. That copy never leaves your device and is gone when you close the tab.
We do not sell anything to anyone, and there is nothing to sell. There are no advertising trackers on this site.
Why we are allowed to hold it
The account itself, and everything needed to run it, on the basis that you asked for an account and it cannot work otherwise. Marketing email on the basis of your consent, which is a separate unticked box and which you can withdraw at any time without losing the account. The optional fields on the basis of your consent, given by choosing to fill them in.
Where it goes
The site runs on Vercel, the database is Neon, and email is sent by Resend. Web requests are served from Frankfurt and email is sent from within the EU. The database is currently in the United States and is being moved to the EU; until it is, your information is transferred outside the EU and outside Morocco. You are told this before you create an account, and creating one is how you agree to it. This paragraph will be updated the day the move happens rather than in advance of it.
How long it stays
For as long as you have an account. The rate-limit counters — the ones holding your email address and your IP address — are swept every hour, and each sweep takes every counter whose window opened more than two hours ago, so the longest any of them can live is three hours. The two-hour margin is there because a request arriving on a boundary is still being counted against the window it started in. A password parked by an unfinished sign-up stops working after fifteen minutes and is deleted by the next sweep. Archived votes are kept without an expiry, because a past result nobody can check is not a result — and the account id on one can be stripped on request while the count stands.
What you can do
Delete everything, yourself, immediately. Your account page has a delete button. It removes the account, the password, the sessions, your current vote and anything you have suggested. It cannot be undone, and nothing that still identifies you is kept.
Two records outlive the account, and neither of them is a copy of it. A vote archived from a closed round stays in that round’s count, carrying the account id it was cast under — once the account is gone there is nothing left that matches that id to a person, and a tally that changes every time somebody leaves is not a tally. The amount, currency and date of any tip stay as well, because a payment that disappears with the payer cannot be reconciled against Stripe afterwards; the link to your account comes off the moment the account goes. Your address also sits in a rate-limit counter for up to three hours afterwards, as above.
You can also correct anything on that page, stop the email from any email or from the same page, and ask us for a copy of what is held. Write to hello@zetamethod.com and you will get an answer within thirty days. If you are in the EU you can complain to your national data protection authority; in Morocco, to the CNDP.
Age
Accounts are for adults. We do not knowingly hold data about anyone under 18, and where a birth year says otherwise the account is refused and nothing about the attempt is stored.
Changes
If this page changes in a way that affects you, you will be told by email before it takes effect rather than after.