Marginal — Highlight, Read & Summarize

Marginal is a highlighter and note-taking extension for anything you read in Chrome — regular webpages and PDFs alike. HIGHLIGHT ANYTHING Select text on any page or PDF and save it as a highlight in one click. Choose from multiple highlight colors to organize by topic, priority, or however you think. ANNOTATE WITH NOTES Add your own notes to any highlight. Tag highlights, organize them into folders and subjects, and search across everything you've saved. WORKS ON PDFs TOO Open a PDF (local file or a link) and Marginal highlights it exactly like a webpage — including a page-by-page view in the side panel, real page thumbnails, and jump-to-page navigation. DISTRACTION-FREE READER MODE Strip away ads, sidebars, and clutter to focus on the actual article. VIDEO NOTES FOR YOUTUBE, UDEMY, COURSERA, KHAN ACADEMY, EDX Snap a frame from a lecture video as a note, or generate an AI summary of what you're watching, complete with timestamps. AI SUMMARIES — YOUR KEY, YOUR CHOICE Bring your own API key for Anthropic Claude, OpenAI, or Google Gemini, or use Chrome's built-in on-device AI where available. Marginal never sees your key or your data — requests go straight from your browser to the provider you chose. 100% LOCAL, NO ACCOUNT REQUIRED Every highlight, note, and folder lives in your browser's local storage. There's no Marginal account, no server, and no sync service reading your data. Nothing to sign up for, nothing to lose if a service goes down. PRIVACY BY DESIGN No analytics. No ad trackers. No data collection beyond what you explicitly save, on your own device. Full privacy policy: [YOUR PRIVACY POLICY URL] FEATURES AT A GLANCE - Highlight & annotate any webpage or PDF - Multiple highlight colors + tags + folders - Full-text search across all your notes - Distraction-free reader mode - Read-aloud (text-to-speech) for any highlight - Video frame capture + AI video summaries (YouTube, Udemy, Coursera, Khan Academy, edX) - AI summaries via Claude, GPT, Gemini, or on-device AI - Export notes to Markdown - 100% local storage — no account, no cloud sync, no ads Whether you're studying for an exam, doing research, or just want to remember what you read, Marginal keeps your highlights where they belong: with you.