Lumen: Knowledge Browser1.4.1 - App Store

Lumen is a browser with a memory.

Most browsers forget the second you close a tab. Lumen does not. As you read, it quietly builds a personal knowledge base from the pages you actually engage with, and then lets you ask questions about any of it in plain English, answered by an AI model that runs entirely on your device. Nothing you read, nothing you ask, and nothing Lumen learns about you ever leaves your phone.

WHAT IT DOES
Lumen reads along with you. It distinguishes between pages you genuinely read and pages you opened and swiped away, and it extracts the meaningful content from the ones that stuck. That content gets summarized, embedded, and organized into a searchable knowledge base, all on-device. Later, when you want to find something, you do not have to dig through history or remember which tab it was in. You just ask:

"What did I read about sourdough starters last week?"
"Summarize that article about the new M-series chips."
"What were the main arguments in that piece I read on Tuesday?"

Every answer cites the pages it came from, so you can jump straight back to the source.

AUTO-ORGANIZED
Your reading sorts itself into a clean hierarchy: Topics, Websites, and Pages. Each level carries its own AI-generated summary, so you can scan what you have been learning at a glance. No tagging, no folders to maintain. Lumen handles it in the background.

PRIVATE BY DEFAULT
Lumen has no server. There is quite literally nothing to send.

On-device LLM: a quantized Llama 3.2 model runs locally through Apple's MLX framework.
Local SQLite storage: your reading history, summaries, and embeddings never leave the device.
Built-in privacy: tracker blocking, third-party cookie blocking, and fingerprint resistance.
Secure: HTTPS-only by default, with mixed-content blocking.

No strings attached: no accounts, no sync, no telemetry, no ads. The AI weights download once on first launch (~700 MB). After that, everything works fully offline: browsing, reading, asking, answering.

BUILT FOR iOS
Lumen is written from scratch in Swift and SwiftUI, designed specifically for iPhone and iPad. It uses Apple's own frameworks wherever it can: NLEmbedding for semantic search, WKWebView for browsing, SQLite with FTS5 for full-text queries, and MLX Swift for on-device inference. Zero third-party trackers. Zero external services.

WHO IT'S FOR
While most browsers treat the web as a feed to scroll past, Lumen treats it as a library worth keeping. If you read a lot online and constantly think "I know I saw something about this recently but I cannot find it again," Lumen is for you. Researchers, students, writers, developers, and lifelong learners.
You do not need to change how you browse. Browse normally, and Lumen takes care of the rest.

REQUIREMENTS
iOS 18 or later. iPhone with Apple Silicon recommended for the fastest on-device AI performance.

Version History - Answers about your saved pages come up faster
- AI replies now stay steady on screen as it's being written
- Search results pages won't get saved anymore, so your folders stay tidy
- Fixed going back through your Topics, Websites, and Pages
- Fixed the dates and grouping on your reading history
- Made the app start up more reliably and run a bit smoother 1.4.1 Jun 19 - Ask a question and Lumen now reaches for the saved pages that actually match it, so answers line up better with what you were reading.
- Made a typo in your question? Lumen quietly fixes it for you, so a small slip won't throw off the answer.
- When there's more than one thing to say, answers come back as a short bulleted list instead of one long paragraph.
- Your saved pages sort into topics more sensibly, and there's a new Anime category.
- The "thinking" indicator now sits right above the text box while Lumen works, instead of drifting elsewhere on screen. 1.4.0 May 27 - Tab switching is smoother. No more flicker when jumping between tabs.
- The URL bar now resizes with a clean, fluid animation instead of snapping.
- Tapping Go always plays the slide-in animation.
- Keyboard pops up faster the first time you tap the URL bar.
- Lumen opens quicker, meaning your history loads in the background instead of
blocking launch.
- Animations across the app now share the same feel, so motion looks
consistent everywhere.
- The URL pill looks cleaner and softer on light-colored websites. 1.3.3 May 16 - The toolbar now picks up the color of the site you're on
- Long-press the tabs button to reopen the last tab you closed
- Tapping a tab in the carousel expands smoothly without a visible jump
- Search history now sits comfortably above the keyboard
- Settings page headers match the rest of the app
- Smoother toolbar animations and cleaner highlight fades 1.3.2 May 14 - URL bar text: tighter, bolder display weight
- Knowledge panel headings, page titles, and section labels: editorial typography pass
- Export modal title and progress label: heavier display type
- Internal: page-color environment foundation for future theming work 1.3.1 May 13 - Fixed rare crashes when capturing knowledge from pages closed mid-load
- Search suggestions now show the top 5 most relevant results
- Tapping a suggestion no longer adds it to your search history
- Cleaned up duplicate entries in browsing history
- Smoother search bar collapse animation, no more lingering text
- Faster, smoother scrolling on the suggestions list
- Background visuals transition more cleanly when switching to and from incognito 1.3.0 May 12 - Fixed a focus issue when swiping up to search.
- Restored the magnifying glass icon in the search bar.
- Cleaner color rendering across bookmarks, the knowledge panel, and home. 1.2.4 May 8 - UI / UX animations for searching and browser fluidity had major improvements.
- AI prompt injection vulnerabilities were reduced and targeted. 1.2.3 May 7 1.2.2 May 5