Local-first Personal Knowledge Base
Every PDF.
Every highlight.
Every video subtitle.
What you've read should stay findable.
Bring documents, webpages, notes and videos into one library. Read, annotate, search and review, with your files stored on your own devices.
One question. Different perspectives.
A case on the web, the theory in a PDF, a comparison on video.
Connect the ideas you find.
Keep a highlight, link to its source, capture a thought from a video.
Your understanding. Its supporting evidence.
Text, source links, screenshots and video clips, together in one note.
Find the sources. And your thinking.
One search brings back your materials and the notes you wrote.
Sources
PDF / EPUB / Web / Markdown / Video
Retrieval
Keyword + semantic search
Long-term use
Annotations, links, cards & spaced review
One Library
Keep different kinds of material together
Collect material from your device or the web, clean it up, and organize it your way. Keep PDFs, ebooks, webpages, notes and videos in one library.
Keep different kinds of material together
Loading demo…Read & Annotate
What you mark while reading keeps working for you
Highlights, quotes, notes and memory cards stay with the source. Find them again through search, links and review, and pick up where your thinking left off.
What you mark while reading keeps working for you
Loading demo…Document Links
Links point to exact places, not just documents
Connect related content to a place in the source. Document addresses keep PDF pages, EPUB reading positions, Markdown paragraphs, MinerU blocks or video times. Use them in link annotations, Markdown notes or another app.
Links point to exact places, not just documents
Loading demo…Search
Search your reading traces, not just the text
Search body text, highlights, quotes, links, notes and flashcards, with priority for the passages you marked. Enable semantic search to find related material in your own words. Your configured AI service can also summarize results with links back to the sources.
Search your reading traces, not just the text
Loading demo…Translate
Read foreign-language materials as you go
Translate any selection instantly in PDFs, EPUBs, webpage snapshots and MinerU documents. EPUB, snapshots and MinerU also support full-text translation — generated paragraph by paragraph, resumable anytime, and exportable as bilingual or translation-only editions.
Read foreign-language materials as you go
Loading demo…Review
What you have read comes back when it is time
Annotations turn into review cards automatically by rules; flip cards and mask cards train active recall. Each review is one tap — hard, okay or easy — and DoCube schedules the next round with spaced repetition, so knowledge stays alive after reading.
What you have read comes back when it is time
Loading demo…Video
Keep the exact moment from any video
A video document puts the player, subtitles, chapter outline, bookmarks and annotations on one page. Videos without subtitles get them from on-device Whisper; subtitles can be translated and annotated, and every annotation carries a time range that jumps straight back to that second.
Keep the exact moment from any video
Loading demo…Export
Take your work with you
Export Markdown, webpage snapshots, EPUB and MinerU documents as original files, reading-layout PDFs or EPUBs, depending on the document type. Translated documents can become bilingual or translation-only editions. Exports are independent copies you can read and use in other apps.
Take your work with you
Loading demo…More
More for deep readers
Recognize text in scans, edit Markdown, organize documents automatically and sync across devices.
OCR for Scans
Add a text layer to scanned PDFs on-device, then copy, search and annotate. Complex layouts can become structured MinerU documents.
Markdown Workbench
Edit with a live preview side by side: math, Mermaid diagrams, mind maps, audio and video, with a full syntax example in every new document.
Dynamic Projects
Combine rules over name, tag, type, import date and reading progress to generate live views like paper reading lists or course notes.
AI When You Need It
Summarize search results, find related material, make flashcards, translate documents or organize video chapters. Choose an online service or local model for each task.
iCloud + Local Sync
Changes merge automatically via iCloud; large files can move device-to-device over local P2P, no cloud involved.
Plans & Stats
Weekly reading and review plans, progress tracking, an activity heatmap and review stats keep long-term habits visible.
Practical Guides
Start with the problem you actually have
Explore practical guides to searching documents, translating ebooks, organizing notes and finding content in videos.
Privacy
Local-first: your data stays yours
DoCube is a library built on your own devices. We believe materials gathered over years should belong to their owner — like a paper notebook.
We never collect or store personally identifiable information, nor any private data created inside the app.
Only fully anonymous usage data and crash reports are collected, solely to improve the app.
All documents, notes and related data live on your devices and sync through your own iCloud account — you stay in control.
Only when you use AI features are the relevant text snippets sent to the AI provider you configured yourself.
Download
One purchase, every device
DoCube runs on Mac, iPhone and iPad, merging changes through iCloud — highlights made on your phone wait exactly where you left them on your Mac.
One purchase, every device
Loading demo…Free
$0
Up to 5 documents, with the full collect-read-annotate-search-review workflow.
Pro
One-time purchase
Unlimited documents, plus translation and format-conversion exports, on all platforms.
Start with your next document — and keep what you read.
Import, annotate, retrieve, link, review. Make deep reading an ongoing practice.