# YouTube Playlist Length Calculator

> Free web app: paste a **public** YouTube playlist URL to sum video durations using the YouTube Data API v3 on the server.

## Primary URLs

- Calculator (home): /
- Blog index: /blog
- FAQ (on home page): /#faq
- About: /about
- Feedback: /feedback
- Contact: /contact
- Privacy: /privacy
- Terms: /terms
- Disclaimer: /disclaimer
- Machine-readable site map: /sitemap.xml
- Crawl policy: /robots.txt

## Behavior

- Accepts playlist URLs or watch URLs that include a `list=` playlist id.
- Optional **From** / **To** slot range filters which playlist items are summed.
- After a successful run, shows total duration and estimated wall-clock time at 1.25×–2× playback speed (informational only).
- Renders a table of videos with titles, indices, durations, and links to watch on YouTube.

## Limitations

- Only **public** content the API can list; private or unavailable videos may be omitted.
- Not affiliated with YouTube or Google. Trademarks belong to their owners.

## API (server-only)

- Browser calls **POST /api/youtube/playlist** with JSON `{ playlistUrl, from?, to? }`. This route is for this website’s UI, not a documented public product API; respect hosting provider and YouTube API quotas and terms.

## Stack (for assistants)

- Next.js App Router, React, TypeScript. Styling: Tailwind CSS v4.