A reading app by Alterras LLC
Luum is a reading app for iPhone. Open an EPUB, a PDF, or a web page; listen to it read aloud at your pace; ask the book questions; and turn what you read into flashcards, quizzes, and spaced review so it sticks. All of it happens on your device.
Luum needs no account. Luum makes network requests only when you ask it to: when you open a web page (Luum fetches that page, and any link you tap in its preview, directly from the website), when you choose to download an optional Labs voice (Luum downloads the voice files from Hugging Face, huggingface.co), when you leave a tip (handled by Apple), when you open the community board, or when you join the newsletter (Luum sends the email you choose to share). There are no analytics, no accounts, and no Alterras server, and nothing else about you is sent anywhere.
Is Luum free?
Yes. Every feature, as many books as you like, no purchase and no subscription.
How do tips work?
If you'd like to support Luum, tap Want to show support? in the reader's ⋯ menu, then Buy me a coffee. A tip is a one off in app purchase through Apple ($2.99, $9.99, or $19.99). It unlocks nothing; every feature is already yours. You can tip as often as you like.
Can I get a tip back?
Tips are handled by Apple, so refunds are too. Request one at reportaproblem.apple.com, or see Apple's guide: Request a refund for apps or content. We cannot issue refunds directly.
How do I delete a book?
Luum 1.0 does not yet have a button to remove a single book from your library. To remove everything — books, cards, and review history — delete the Luum app from your iPhone. Removing individual books is on the list for an upcoming update. You can still remove a book's downloaded audio from the book's audio sheet.
Do I need an account or an internet connection?
No account, ever. You only need a connection to open a web page, download an optional Labs voice, tip, visit the community board, or join the newsletter. Books you have already imported work offline.
Where is my data stored, and what happens if I delete the app?
Everything is stored locally, inside Luum's own app container. Nothing is synced or backed up to us. We have no server and no copy. The one exception is your email, if you join the newsletter. Deleting Luum removes that data, and we cannot recover it for you. Details are in the Privacy Policy.
Why are Ask, cards, or quizzes unavailable?
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. They need an iPhone that supports Apple Intelligence, with Apple Intelligence turned on in Settings. On other devices the rest of Luum works as normal.
Can Luum open DRM-protected books?
No. Luum does not include DRM support, so books protected with Readium LCP or similar schemes will not open. Unprotected EPUB and PDF files work.
I have a feature request or found a bug.
Post it on the Luum community board, or tap Request feature / bug fix in the reader's ⋯ menu. Others can vote on it there, and you'll see when it ships. Prefer email? Write to aziza@alterras.app. Luum is made by one person, and requests genuinely shape what gets built next.
How do I join the newsletter?
Sign up on the web at alterras.app/#newsletter. In app sign up is coming in a later version. We use your email only for the newsletter. To leave or have it deleted, email aziza@alterras.app.
Email aziza@alterras.app — we read every message. This page grows as questions come in, so if yours isn't answered here yet, asking it helps the next person too.
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Last updated: October 18, 2026