Fu-Sen

Select text on any web page or PDF for clear, contextual AI explanations. Save them on the page and revisit them anytime.

Fu-Sen is an AI-powered browser extension that helps you understand difficult content while reading web pages and PDFs. Select text to get an AI explanation right on the page. You can also ask follow-up questions, take notes, and revisit your explanation history. When you request an explanation, the selected text, relevant surrounding context, page title, and page URL (or corresponding PDF information) are sent to Fu-Sen's service and AI-Provider only as needed to generate the requested explanation. You can try basic explanation generation as a guest without signing in. Sign in with Google to use the Free plan and access follow-up questions and note editing.