Save, annotate, and resurface everything you read online with AI-powered search
Memex (by WorldBrain) is a privacy-first browser extension and web research assistant that lets you bookmark, highlight, annotate, and organize everything you read online. Named after Vannevar Bush's visionary concept of an extended memory machine, Memex aims to make your entire web browsing history a searchable, reusable knowledge base. The tool works across Chrome, Firefox, and mobile (iOS/Android), and stores all data locally by default so your reading history never leaves your device. You can annotate websites, PDFs, and YouTube videos, organize content into collections, and use full-text search to find anything you've ever saved. AI-powered features let you summarize pages and chat with your saved content, while an MCP server integration means you can connect your knowledge base directly to LLMs like Claude and GPT. Memex is open-source and operated under a Steward Ownership model — meaning the company cannot be sold to investors. It targets researchers, writers, and knowledge workers who need a durable, private alternative to cloud-dependent bookmarking and note-taking tools.
Works in Chrome and Firefox to capture and annotate any webpage as you browse
Add highlights and notes directly on webpages, PDFs, and YouTube videos without leaving the page
Search across the full text of every page, PDF, and annotation you have ever saved
Organize saved content into named collections and apply tags for flexible retrieval
Summarize any saved page or PDF and ask questions about your saved knowledge base using AI
Connect your Memex knowledge base directly to LLMs like Claude and GPT via the Model Context Protocol
All data stored on your device by default — no cloud upload required for privacy
iOS and Android apps let you save and annotate content on the go
Fully open-source codebase available on GitHub for transparency and community contributions
Share annotated pages and collections with teammates or the public