Lumen Support

Lumen is a native iOS PDF reader with a built-in AI assistant. We’re happy to help.

Contact us

Email emilio.arnold99@gmail.comand we’ll get back to you. Please include your iOS version and a short description of the issue.

Frequently asked questions

How do I import a PDF?

Tap the +button in your library and pick a file from Files, iCloud Drive, or another app’s share sheet. Your documents stay on your device.

How does “Ask AI” work?

Open a PDF and tap Ask AI to chat with the document — request summaries, explanations, or answers to specific questions. You can also highlight a passage and ask Lumen to explain just that text. Answers are generated by an AI model and may occasionally be imperfect, so verify anything important.

What is Lumen Pro?

Lumen Pro unlocks unlimited AI chat, every reading theme (Sepia and Night), and cloud sync. It starts with a 7-day free trial, then bills weekly or yearly. You can manage or cancel anytime in Settings → Apple ID → Subscriptions; a subscription renews unless canceled at least 24 hours before the end of the current period.

How do I restore a purchase?

Open the paywall or Settings inside Lumen and tap Restore Purchaseswhile signed in with the Apple ID you used to subscribe.

Is my data private?

Your PDFs, reading progress, and chat history are stored locally on your device. When you use the AI assistant, the relevant document text and your message are sent over an encrypted connection to our stateless backend, which forwards them to Google’s Gemini API to generate a reply and stores nothing. See our Privacy Policy for details.