Launching Kioku: private second brain

What is Kioku

It's a personal, private and free Second Brain app I built. You can think of it as an editor and reader that blends Bear's clean UI with Obsidian's rich functionality: web crawler, free sync across Apple devices, pure markdown files, 100% local, Excalidraw, PDF support.

Why make this?

Personally, I want to build a knowledge base asset over time, and leverage AI to help me search and learn from this knowledge base. Existing solutions and why they fail:

• NotebookLM: Very nice integration with AI, and I like the fact that you can make it a podcast. But users don't own the content.
• Bear: Not raw markdown, no AI.
• Obsidian: Great but too cluttered with all the plugins.

So I created Kioku, and its goal is to manage a private knowledge vault, synced across devices. And users can choose their favorite AI like Claude, Codex, Gemini, ... to query on this knowledge base. Kioku also allows users to use on-device models like Gemma to query their documents without any network request.

How to use it

Capture

You can save a blog, PDF paper easily

You can also write your own markdown, excalidraw from the macOS Kioku app.

Read

Contents are synced via private iCloud. Kioku doesn't have any server or see any content from users.

Future

1. Provide easier ways to capture user thoughts on mobile devices. I'm thinking of a chat-like interface where users can send short messages, voice messages quickly and easily from their phone. And all thought sparks will be stored safely.

2. Integrate on-device AI for an AI learning experience.