Luum — Privacy Policy

The short version

Luum collects nothing unless you join the newsletter, and then only your email. There is no account, no cloud sync, no analytics, and no tracking. Everything you read, capture, and review stays on your device.

Data we collect

Only one thing, and only if you choose to: your email address, when you join the newsletter. It is used for the newsletter and nothing else. In Apple's terms that is Contact Info › Email Address, linked to you, for the developer's marketing. For every other category Apple asks about, Luum's answer is Data Not Collected.

The newsletter

What we keep. Your email, plus the Luum version, your device model, and the time you joined. Signing up on the web works the same way.
Where it lives. In a Google Sheet in Alterras's own Google Workspace account. It is not sold or shared with anyone.
Sign in with Apple. If you tap Continue with Apple, it is used only to hand Luum your email. Apple lets you share your real address or a private relay address; either works. No account is created.
Leaving. Email aziza@alterras.app and we will delete your address.

Data stored on your device

Your library. Books, documents, and web pages you add are stored inside Luum's own app container on your device. They are never uploaded.
Your captures, cards, and review history. What you highlight, the flashcards and quizzes you make, your Ask conversations, and your review schedule are saved locally on your device and stay there.
Audio. Read-aloud audio is generated on your device. Any audio you download for offline listening is stored on your device.
Preferences. Reading settings such as theme, voice, and pace are stored locally on your device. No account is required to use the app.

Because none of this leaves your device, deleting Luum deletes it. We have no copy and no way to recover it.

Network access

Luum makes network requests only when you ask it to:

Opening a web page. You paste or share a link yourself. Luum requests that page — and any link you tap in the preview — directly from the website, not from any Alterras server. The article is processed on your device. The request carries no account and no Luum identifier.
Labs voices. If you choose to download an optional Labs voice, Luum downloads the voice files from Hugging Face (huggingface.co). Like any web server, Hugging Face receives your IP address with that request; Luum sends nothing about you.
Joining the newsletter. Luum sends the email you choose to share, with the details listed above.
The community board. Request feature / bug fix opens luum.alterras.app in a Safari view, which forwards to alterras.app/community-feedback. The link carries your Luum version and device model so a bug report arrives with its context. The board is a website run by Alterras: what you post there is public. Posting or voting asks for your email, which is never shown; it counts your vote once and lets us reply about your post. An optional box signs you up for news about new apps and newsletter posts: it sends a confirmation email first, through Brevo, the email service Alterras uses for that list, and every email has a one-click unsubscribe. Ask us at the address below to remove your posts or your email.

On-device intelligence and voice

Ask, flashcard drafting, and quizzes use Apple Intelligence, which runs on your device. Voice questions use Apple's on-device speech recognition. None of it goes through an Alterras server. Apple's handling of on-device features is described in Apple's Privacy Policy.

Tips

Tips are in app purchases handled entirely by Apple through the App Store (StoreKit). A tip unlocks nothing. Alterras does not receive your name, email, payment details, or any other personal data from a tip. Refunds go through Apple at reportaproblem.apple.com.

Data we do not collect

No analytics or usage tracking
No crash reporters or telemetry
No advertising or ad identifiers
No third-party SDKs that collect data
No record of what you read, when you read it, or how long for

Third-party services

Luum uses open-source components to open and display books. They run entirely on your device and send nothing anywhere. Newsletter emails are stored with Google, as described above. Luum uses no analytics platforms, no crash reporters, and no advertising networks.

Children's privacy

Luum is not directed at children and does not knowingly collect a child's email. If you believe a child has joined the newsletter, email us and we will delete it.

Changes to this policy

If Luum's behaviour changes in a way that affects your privacy, we will update this page and revise the date below before that version ships.

Contact

Questions about this policy? Reach us at aziza@alterras.app.

Effective date: October 18, 2026