Cognito
Your Second Brain for Reading
An AI-powered reading companion for iPhone and iPad that turns passive reading into active understanding. Chat with your EPUBs and PDFs, extract insights instantly, and never lose track of what matters.
Key Features
💬 Contextual Chat
Ask questions about specific characters, plot points, or arguments. Get answers grounded strictly in the book's text, from "What are the key arguments in Chapter 3?" to "Explain this like I'm 5."
🔍 Semantic Search
Find concepts, not just keywords. Cognito's vector-based RAG engine understands the context of your library, helping you locate ideas across all your documents.
🧠 Hybrid AI Intelligence
Uses Apple Intelligence for private, on-device processing, with cloud fallback to powerful models (via OpenRouter) only when deeper analysis is needed.
🔒 Privacy-First Design
Your library lives on your device. No user accounts required. You own your data and your API keys. Built on Apple Intelligence for privacy-first AI.
✨ Liquid Glass Aesthetic
A modern design language utilizing .ultraThinMaterial, soft gradients, and fluid spring animations that feel native to the latest iOS ecosystem.
How It Works
1. Import Your Library
Add EPUB (via Readium) and PDF (via PDFKit) files to your personal library. All files stay on your device.
2. Read & Highlight
Read with a clean, customizable interface. Highlight important passages and add notes with haptic feedback and smooth transitions.
3. Ask & Search
Stuck on a concept? Ask the AI anything about the book or use semantic search to find related ideas across your library.
4. Summarize & Retain
Get instant chapter summaries, extract key insights, and save important findings to your knowledge base.
Your Privacy Matters
- No user accounts required
- All books stored locally on your device
- On-device AI processing with Apple Intelligence
- Optional cloud AI with anonymous connections only
- You control your data and API keys
Technical Details
Built using a modern, forward-looking stack designed for iOS 18 and beyond:
- Swift 6 with native concurrency and Actors
- SwiftUI for fluid interfaces with
.ultraThinMaterial - SwiftData for schema-driven, iCloud-ready persistent storage
- Apple Intelligence via FoundationModels framework for on-device AI
- Custom RAG Engine with SQLite-powered local vector store and intelligent chunking
- Readium & PDFKit for high-fidelity EPUB and PDF rendering
- OpenRouter Integration for secure, anonymous cloud AI fallback
iPhone Screenshots
iPad Screenshots
Developer
Cognito is built by Sérgio Caiado as part of Tiny Little Lab, an independent one-person studio exploring AI-powered iOS apps.
Need Help?
Have questions or feedback? Reach out via email or GitHub.