Knowledge Base: Second Brain

AI grows your second brain

Only for iPhone

Free · Designed for iPhone. Not verified for macOS.

iPhone

Stop reading and forgetting. Save an article and AI keeps weaving it into your own evolving encyclopedia — key points up front, answers with citations, all on-device. ■ Knowledge that grows on its own Just save the articles you find interesting — AI quietly compiles them into your own encyclopedia in the background. Knowledge Base is the gentle second brain that helps you graduate from "read once, forget forever." ■ Save from anywhere, in one step - Save articles directly from Safari or any app's Share Sheet - The + button also lets you add URLs, text, PDFs, photos (OCR), and audio (transcription) - Non-English or non-Japanese content is automatically translated into your chosen language before it's organized Saving finishes instantly — the heavy lifting happens in the background, so you're never kept waiting. ■ AI organizes key points by topic AI automatically creates and updates "concept pages" — your own personal wiki — across multiple articles. Open the Knowledge tab and topic summaries are always shown up to date. - The most important points come first, no tapping required - Related concepts link to each other automatically, so your knowledge connects - Every page can always be traced back to its original article ■ Chat that answers with citations "What did that article actually say again?" Ask the AI Chat. - Answers are generated only from the articles you've saved - Tap a citation number to jump straight to the source article - When general knowledge is used to fill a gap, it's always labeled clearly ■ Fix AI's mistakes in one sentence - Tap "Correct" on any article's detail page and describe the fix in plain language (e.g. "Claude Code is being misread as something else") - Unwanted concepts or tags can be edited, merged, or hidden anytime You always stay in control. ■ Privacy by design - All AI processing runs entirely on-device via Apple Intelligence - No ads, no tracking, zero data sent to external servers - iCloud sync uses only your own private database ■ A calm, considered aesthetic A palette of sumi ink and washi paper, elegant Mincho headlines, and breathing negative space inspired by seigaiha waves. Every time you open it, it feels quiet and refined. ■ Languages Knowledge Base supports 4 interface languages: English, Japanese, Simplified Chinese, and Traditional Chinese. AI-generated summaries, concept pages, and chat replies follow the same language, chosen automatically from your device's language on first launch (you can change it anytime in Settings > Generation Language). ■ Requirements (important) - AI features (automatic concept-page generation, AI Chat, summaries, translation, auto-tagging) require an iPhone that supports Apple Intelligence - Please turn on Apple Intelligence in Settings before use - Even without Apple Intelligence, you can still save, search, browse, and organize tags for your articles Now, put your iPhone's AI to full use and turn everything you read into knowledge that's truly your own.

Ratings & Reviews

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Knowledge Base v1.1 is here. ・Now supports 7 languages: Japanese, Simplified Chinese, Traditional Chinese, English, Korean, Spanish, and German. Both the UI and AI-generated summaries, concept pages, and chat replies follow your chosen language ・A banner now explains why and how to fix it when Apple Intelligence isn't available ・A banner also lets you know if your device language and generation language don't match ・When AI becomes available again, any paused organizing automatically resumes Feedback and bug reports are welcome via GitHub Issues.

Version 1.1

The developer, CHANG CHIA-WEI, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Collected

    The developer does not collect any data from this app.

    Privacy practices may vary based, for example, on the features you use or your age. Learn More

    Accessibility

    The developer has not yet indicated which accessibility features this app supports. Learn More

    Information

    Provider
    • CHANG CHIA-WEI
    Size
    • 9.3 MB
    Category
    • Lifestyle
    Compatibility
    Requires iOS 26.4 or later.
    • iPhone
      Requires iOS 26.4 or later.
    • Mac
      Requires macOS 26.4 or later and a Mac with Apple M1 chip or later.
    • Apple Vision
      Requires visionOS 26.4 or later.
    Languages
    English and 6 more
    • English, German, Japanese, Korean, Simplified Chinese, Spanish, Traditional Chinese
    Age Rating
    4+
    Copyright
    • © 2026 Chia-Wei Chang
  • Developer Website
  • Privacy Policy

    • More by CHANG CHIA-WEI

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