Kioku: private second brain

Save web pages, PDFs, notes, and ideas into a private Markdown library built for offline reading, focused study, and on-device recall.

Kioku is a personal knowledge library for Mac. Save articles, PDFs, websites, and your own Markdown notes into organized vaults you can read, search, annotate, and keep with you offline.

Use Kioku to turn scattered research into a calm, durable library. Paste a URL to archive a single page, save a PDF from your Mac, or crawl more of a site when you want a deeper reference vault. Kioku stores your content as Markdown with downloaded assets, so your library stays portable and readable outside the app.

Write your own notes with a focused Markdown editor, add images, create internal links, and keep authored notes separate from saved web pages. While reading, select passages to save excerpts and notes so important ideas do not disappear after the first pass.

Kioku also includes optional local AI features for summaries, retrieval, chat, and study cards. Supported models run on your Mac, keeping those experiences local to your device.

Features:

Save articles, PDFs, pages, and websites into Markdown vaults Read saved content offline in a native Mac interface Write and edit Markdown notes Organize saved pages into vaults Search your library Annotate passages and save excerpts Generate summaries with optional on-device AI Create study cards from saved pages and notes Store content in a local or iCloud Drive-backed folder Keep your library portable with Markdown files and assets Kioku is for readers, researchers, students, builders, and anyone who wants a quieter place to collect what matters.