Hidden America

Privacy Policy

Last updated 26 August 2026

The short version. We collect nothing. There is no account, no sign-up, no analytics, no crash reporting and no advertising identifier — the app sends us nothing at all, and we could not identify you if we wanted to. The National Register ships inside the app, so browsing it is entirely offline. Your passport, your notes and your API key stay on your phone. Three outside services see a request when you use the features that need them, and each is named below.

Who we are

Hidden America is made by PTK Studio. This policy covers the Hidden America iOS app and this page. If anything here is unclear, write to hello@ptk-studio.com and we will answer plainly.

What we collect

Nothing. The app contains no analytics, no crash reporting and no advertising or attribution SDK of any kind. It never contacts a server of ours — we do not run one. We do not know how many places you have looked at, which state you browsed, or whether you opened the app at all.

Because we hold nothing about you, there is nothing for us to sell, share with data brokers, or use to advertise to you. There are no ads in the app.

What stays on your device

Your passport — the places you marked visited, your notes, what you took away from each, and the dates.
Places you saved for later.
Your Anthropic API key, if you added one. It is held in the iOS keychain.
Any style, era or theme the guide worked out for a listing, cached so it is only ever worked out once.
The National Register snapshot itself — all 90,180 listings ship inside the app.
Your settings.

These live in the app's own storage. We have no copy and cannot read them. Deleting the app deletes them.

What the app sends, and to whom

Three services, each for a specific job, and none of them ours:

The National Park Service (mapservices.nps.gov) receives the rectangle of the map you are looking at, so the app can pick up listings added since the snapshot was cut. If you are looking at your own surroundings, that rectangle necessarily describes roughly where you are.
The Library of Congress (loc.gov) receives the name and town of a place when you open it, so the app can find archival photographs of it. That tells them which place you opened, not who opened it.
Anthropic (api.anthropic.com) receives a request only if you have added your own API key, and only when you ask for something. What goes with it depends on what you asked for: the listing's federal record and the titles of the photographs matched to it for a written history; the photograph you captured or chose for Then & Now; and for identifying a building, the photograph together with your coordinates and the direction you are facing.

The app has no key of ours and no account with Anthropic. When you use the guide you are using your own Anthropic account under your own agreement with them, and their handling of those requests is governed by their privacy policy. Remove the key in Settings and the app stops contacting them entirely.

Tapping through to a nomination file at the National Archives, or to an item at the Library of Congress, opens that page in your browser in the ordinary way.

Permissions the app asks for

Location, while you are using the app. Used on the device to show what is around you and to sort places by distance. It is sent nowhere, with the single exception described above: identifying a building from the camera sends your coordinates and heading to Anthropic, because that is what the question requires. Decline the permission and the rest of the app works — browse, search and the map all function without it.
Camera. Used for identifying a building and for lining up a historical photograph against the view in front of you. A frame leaves the device only when you press the shutter and ask for one of those two things. The app does not record video and never uses the camera in the background.

When you pick an existing photograph instead of taking one, iOS hands the app that single image and nothing else — the app has no access to your photo library.

What the app never touches

Your name, email address, phone number or any account — there is no sign-up.
Your contacts, calendar, microphone, health data or photo library.
Your advertising identifier. The app does not ask to track you across other companies' apps and websites, so you will never see an App Tracking Transparency prompt.
Location in the background, or when the app is closed.

Children

Hidden America is not directed at children under 13, and we do not knowingly collect personal information from anyone — we do not collect any. If you believe a child has provided us with personal information, contact us and we will delete it.

Your choices and rights

Use it without a key. The map, search, browsing, the federal record and the passport all work with no Anthropic key at all, and in that state the app contacts Anthropic never.
Decline location and camera in iOS Settings at any time. Both are optional and the app degrades gracefully rather than refusing to run.
Delete the app to remove everything it holds, including your key.
Ask us anything, or ask us to delete something, at hello@ptk-studio.com. Depending on where you live you may have rights to access, correct or delete your personal information. We honour those requests regardless of where you live — though in practice we hold nothing to give you, and we would rather say so plainly than pretend to a process we do not need.

Changes to this policy

If the app starts sending anything it does not send today, we will update this page and change the date at the top, and note it in the release notes.

Contact

hello@ptk-studio.com