Proof is a visual feedback and website review platform that helps designers, developers, and their clients collaborate more efficiently. Upload any website URL and Proof automatically captures desktop and mobile screenshots. Reviewers can pin comments directly on the design, reply in threads, attach files, and resolve feedback — all without needing an account. Features include real-time notifications, Slack integration, multi-page support, customizable accent colors, and a generous free tier. Whether you're a freelancer collecting client feedback or an agency managing multiple projects, Proof eliminates the confusion of scattered emails and vague revision notes by keeping all feedback visual, organized, and actionable.