Kioku: private second brain

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.