Whetstone. Last updated 25 August 2026.
The short version. Whetstone has no accounts. It never asks for your name, your email address or your phone number, and there is nothing to sign up for. It records how you did at its tasks, and that is all it records. Nothing goes to advertisers, analytics services, or any other company. One button in Settings deletes everything, from your phone and from our servers, and nothing is kept back.
This summary is not the policy. The rest of the page is.
Whetstone is a general wellness app for training sustained attention, made by Citadel of the Mind Software LLC, a California limited liability company. In this policy, “we” and “us” mean that company.
How you performed, in detail. For every session you do:
Three answers before each check-in. The app asks what kind of place you are in, how noisy it is, and how well you slept the night before. These are fixed choices, not free text. “Where are you” means a category such as “at home” — it is not your location, and the app never asks your device where you are.
What you are using. Your device model, operating system, and whether you are using the app or a browser. Response timing varies by tens of milliseconds between handsets, so sessions cannot be compared without knowing what recorded them.
Two random identifiers. One is created by our sign-in provider when the app first runs; the other is generated by the app itself. Both are random strings. Neither is derived from anything about you or your device, and neither can be traced back to a person by us or by anyone else.
Your privacy choices and when you made them — which of the three boxes at first run you ticked, and the date.
Your name. Your email address. Your phone number, postal address or date of birth. Any payment details. Your location. Your contacts, photos, calendar, microphone or camera. An advertising identifier. Anything at all from any other app on your device.
There is no analytics service in this app, no crash reporter, no advertising software, and no tracking pixel. We have not added one and we do not intend to. If that ever changes, this page changes first.
The app stores data on your device — your sessions, and a token that keeps you signed in to the anonymous account. That is not used to track you across websites, and we set no advertising or analytics cookies.
To run the app. The training level has to carry over between sessions, the schedule has to know where you are in it, and a check-in is meaningless without the ones before it. This is the required consent and Whetstone genuinely cannot work without it.
To study what these tasks measure — only if you agree separately. Whether training like this does what the field claims is an open question, and answering it needs data from many people. If you ticked the research box, your sessions may be used in that work, including by academic researchers we collaborate with, and in anything published about it. Published work describes patterns across many people, never an individual.
Ticking that box is optional, Whetstone behaves identically either way, and you can change your mind at any time in Settings. Untick it and we stop including your data from that point on. Anything already published cannot be unpublished — that is a limit of how research works rather than a policy of ours, which is why we say so plainly rather than burying it.
How you slept has a box of its own. Your sleep answer is the one thing here that could reasonably be called health information, so it is treated separately: it is sent to our servers only if you ticked that third box specifically, and that box cannot be ticked without the research box above it. If you leave it unticked, your sleep answers stay on your device and are never uploaded. If you tick it and later change your mind, the sleep answers already on our servers are erased the next time the app connects — not just withheld from then on.
We do not use any of this to build a profile of you, to make decisions about you, to advertise to you, or to train any product other than Whetstone itself.
We do not sell your data, and we never share it with advertisers. There are exactly two ways it reaches anyone else:
We would also disclose data if the law required it of us. Nothing else.
Every session is written to your own device first, so a bad connection can never cost you one. It is then copied to our database, which is hosted in the United States, in Northern Virginia.
Rows are protected so that the anonymous account which wrote them is the only one that can read them. The app itself can only add rows — it has no ability to alter or overwrite a session already recorded, including your own.
Until you delete it. We do not expire old sessions, because a measurement is only worth having next to the ones that came before it. There is no backup copy held back after a deletion.
Settings → Delete everything. One confirmation, and it goes: every session, your training level, and your privacy choices, from your device and from our servers. There is no soft delete and nothing is retained in a form we could restore.
If your device is offline when you press it, your phone is cleared straight away and the copy on our servers is removed automatically the next time the app connects. You do not have to do anything else, and there is nothing to try again.
Because there is no account and no email address, this button is the only way to exercise any right over your data — there is no identity for us to verify you against, so there is no support route that could act on your behalf. That is why it is on the main Settings screen rather than buried, and why we would rather you knew it was the mechanism.
The California Consumer Privacy Act gives you rights to know what is collected about you, to have it deleted, to have it corrected, and to opt out of its sale or sharing. We do not sell personal information and we do not share it for cross-context behavioural advertising, so there is nothing to opt out of.
The rights to know and to correct are limited by what we hold. We have no name, no email address and no other identifier that could connect a set of sessions to you as a person, so we cannot look you up and cannot tell you what we hold about you. The right to deletion is not limited in the same way: the delete button in Settings carries it out directly, from the device that holds the identifier, without our involvement. If you believe we hold data about you and want to raise it, write to us at the address below.
We will not treat you differently for exercising any of these rights. Nothing in the app is withheld from anyone who declines the optional boxes.
Whetstone is for people aged 18 and over. We do not knowingly collect data from anyone younger. If you believe a child has used the app, write to us and we will delete what we have.
If data held by us is ever exposed or accessed without authorisation, we will notify the people affected, and the Federal Trade Commission, as required by the Health Breach Notification Rule — within 60 days of discovering it, and sooner where we can. With no email addresses on file, notice would be given in the app and on this page.
If we change it, the date at the top changes and the current version is always here. If a change would mean collecting something this page does not currently describe, we will ask you again in the app rather than relying on an updated page you never saw.