Uploading a video and letting reviewers leave timestamped comments shares this register's video-hosting buildable core. Frame-accurate scrubbing and version comparison are the fiddlier part, same as Frame.io's case.
Borderline
Effort: a weekendRunning cost: $8–$16/mo
Why CanICodeThis says Borderline
Video upload and playback shares this register's video build spec
Timestamped text comments tied to a moment in the video are a well-understood data model
Uploading a new version and listing it alongside the original is straightforward file versioning
The parts that'll cause problems
Frame-accurate scrubbing and drawing annotations directly on a specific video frame needs careful player-level engineering
Real-time presence (seeing a teammate's cursor live on the video) compounds the real-time collaboration challenge
Video hosting and delivery at scale shares the real infrastructure concerns every video app on this register has
How I'd build this
frontend
Next.js
database
Supabase
hosting
Vercel
MVP scope
Upload a video and generate a watch page
Timestamped text comments per reviewer
Upload and compare a new version against the previous
Postpone to v2
Frame-level drawing annotations
Real-time cursor presence
Approval workflow (approved/needs changes status)
What it actually costs to build
AI agent — with a subscription (Claude Pro/Max, Cursor, etc.)
$0 marginal
AI agent — pay-per-use API, no subscription
$43–$86 one-time
Hosting, once it's running
$8–$16/mo
Domain name, if you want your own
~$12/yr
Existing tools solving a similar problem typically run $15–$20/mo — see how they compare below.
The build prompt
Build me a video review tool: upload a video, generate a watch page, and let reviewers leave timestamped text comments tied to a specific moment. Support uploading a new version and comparing it against the previous cut. Host video through an existing video service. Skip frame-level drawing annotations for v1.