MarkUp.io is a collaborative visual feedback and review platform that helps teams collect clear, contextual comments directly on websites, images, PDFs, videos, and 30+ other file types. Teams can upload content, create MarkUps from live websites, share review links with clients or stakeholders, and manage feedback in one centralized workspace. Guest reviewers do not need to create an account to leave feedback. They can open a shared link, click directly on the content, and comment. This makes review cycles easier for clients, stakeholders, and external collaborators while helping teams reduce back-and-forth, avoid scattered feedback, and cut down review loops by up to 80%. MarkUp also includes a Chrome extension so users can create new MarkUps directly from their browser. It is especially useful for marketing teams, creative agencies, web teams, video teams, UX/product teams, and client-facing review workflows, while remaining flexible enough for any team reviewing digital content.