YouLoop repeats a selected segment of a YouTube video in your browser.
Open youloop.leftium.com, choose a video and its
A/B bounds, then use the editor's Share URL link to share the clip. Clips repeat by default;
once plays the selection once and pauses at B.
- Watch a clip:
/<videoId>/A~Bopens the watch view. - Edit the same clip:
/?v=ID&t=A~Bopens the editor. The watch view's Edit action preserves the clip. - Legacy
/s?v=ID&a=A&b=Bwatch links and/?v=ID&a=A&b=Beditor links still work.
See Player and clip contracts for URL validation, playback flags, timeline modes, and Fit/Fill behavior.
Use Node 24 and the pnpm version pinned in package.json:
pnpm install --frozen-lockfile
pnpm devRun pnpm check, pnpm lint, pnpm test:clip, pnpm test:share-url,
pnpm test:metadata, pnpm build, and pnpm test:browser.
Install browsers once with pnpm exec playwright install chromium webkit.
The routine browser suite blocks external requests; pnpm test:browser:advisory
provides broader, on-demand coverage with live YouTube. Knip and Fallow audits
are advisory.
See AGENTS.md for test lifetimes, routine gate admission, and retirement. The development guide covers command selection, offline limitations, DevTools checks, audits, and baseline maintenance.
Pushes to main deploy to the Git-connected Vercel project; other branches and
pull requests receive Preview deployments. pnpm build produces the server
artifact in .vercel/output/. Hosting CI also builds with YOULOOP_RUNTIME_PROOF=1
and runs test:hosting and test:social against the production-mode server.
See Deployment and social previews for preview validation, metadata checks, production operation, and rollback.
| Guide | Contents |
|---|---|
| Agent policy | Test lifetimes, gate admission, retirement, and soft budgets. |
| Development | Required/advisory checks, browser probes, and code-quality audits. |
| Player | Editor/watch and URL contracts, timeline, framing, and crop history. |
| Mobile Safari | Scroll layout, device findings, limitations, and verification checklists. |
| Deployment | Vercel, SSR/social metadata, runtime proof, rollback, and historical reports. |
| Browser profiling | Measured suite costs, pruning decisions, and accepted gaps. |