Loop
Loop is a Mac app that turns any file into your own branded link, and follows every open, page and signature.
Loop shares any file as your own branded link: a cut of a film, a storyboard PDF, a deck or a whole website. Viewers leave notes pinned to a moment in a video, draw on PDFs and pictures, and sign in order, with no account. You see who watched and how much of it. It is $49 once, with files in your own Cloudflare account.
Frame.io
Frame.io is a review platform from Adobe where creative teams comment on video, frame by frame, and share the result.
You upload video, photos, design files and documents, and send a share link. Reviewers open it without an account and leave comments, or draw on the frame. It connects to Premiere, Final Cut Pro and Lightroom, and Pro adds branded shares, a passphrase, link expiry and download control for up to 5 members. Pro is $156 a member a year billed yearly, and Adobe Creative Cloud All Apps includes a version with two users.