Crux Cards

About

Stop drowning in browser tabs. Start building a knowledge library that thinks.

Every day, you discover valuable information while browsing—insightful articles, expert opinions, data that could change your thinking. Yet most of it vanishes into forgotten tabs, lost bookmarks, or the void of "I'll remember this later."

Crux Cards transforms how you capture and recall knowledge.

What It Does

Crux Cards automatically extracts the essence of any webpage and turns it into structured, atomic knowledge cards. Each card captures a single insight in one of six semantic types:

Concepts: Definitions and mental models

Facts: Specific data points and events

Quotes: Memorable statements worth preserving

Arguments: Claims backed by evidence

Frameworks: Processes and methodologies

Theses: Investment ideas with catalysts and risks (perfect for analysts)

Unlike traditional bookmarks that just remember URLs, Crux Cards understands what matters on each page and builds connections automatically.

Why Users Love It

Effortless Capture

Click the extension icon on any webpage to generate knowledge cards

AI automatically identifies and structures key insights

Works on articles, PDFs, YouTube videos, and more

Select specific text to create focused cards

100 free credits to get started

Intelligent Organization

Auto entity extraction identifies people, companies, and key concepts

Build an effortless knowledge graph without manual tagging

Entity Timeline tracks how your understanding evolves over time

See all cards related to any person, company, or topic in chronological order

Organize cards into custom folders

Smart Recall

Related cards automatically surface when browsing similar topics

Ask AI to query your personal knowledge base in natural language

AI-powered similarity search finds connections you'd miss

Your library grows more valuable with every card saved

No more "I know I saved this somewhere..."

Built for Retention

Spaced repetition system with daily review queue

Smart scheduling ensures long-term retention
Active recall strengthens memory better than passive re-reading

Track your learning progress over time

Thesis Tracking (Investors)

Purpose-built cards for tracking investment ideas

Document entry points, catalysts, and risks
Track P&L performance alongside your thesis

Entity Timeline shows how your view of companies evolves

Privacy-First

Your cards are stored securely in your personal database

Only you can access your knowledge library

No data mining or selling your insights

Google Sign-In for seamless authentication

Perfect For

Research Analysts building searchable knowledge bases

Portfolio Managers tracking theses and entity timelines

Students using spaced repetition for long-term retention

Knowledge Workers curating insights for projects

Lifelong Learners building their personal knowledge graph

Writers collecting quotes and research for articles

Investors documenting investment theses and tracking performance

How It Works: Capture → Organize → Recall

Browse the web as you normally would

Click the extension when you find something valuable

Review AI-generated cards capturing key insights

Save to folders and let AI extract entities automatically

Rediscover knowledge through related cards and Ask AI

Reinforce learning with daily spaced repetition reviews

Key Features

✓ AI-Powered Extraction - Powerful LLM identifies and structures insights automatically ✓ 6 Semantic Card Types - Concepts, Facts, Quotes, Arguments, Frameworks, Theses ✓ Auto Entity Extraction - Build a knowledge graph without manual work ✓ Entity Timeline - Track how your understanding evolves over time ✓ Ask AI (RAG) - Query your knowledge base in natural language ✓ Smart Related Cards - Surface relevant saved knowledge while browsing ✓ Spaced Repetition - Daily review queue for long-term retention ✓ Thesis Tracking - Purpose-built for investment research ✓ Multiple Content Types - Works with articles, PDFs, videos, and text selections ✓ Personal Knowledge Base - Build your second brain in the cloud ✓ Beautiful Design - Premium typography and thoughtful UX ✓ Cross-Device Sync - Access your cards from anywhere ✓ Search & Filter - Find exactly what you need instantly

Beyond Bookmarks

Traditional bookmarks are like writing down a library's address instead of the book title. They remember where you found information, not what the information was.

Crux Cards captures the actual knowledge, structures it semantically, extracts entities automatically, and surfaces it when you need it most. It's not a filing system—it's a thinking partner.