Instant YouTube Downloader Tool -- 2

I need a small web-app that lets a user paste any public YouTube URL and receive an immediate download in either MP4 or MP3. Only 1080p video quality is required for launch; no lower resolutions are necessary right now. Processing has to feel near-instant, with a secure backend that never exposes our API keys or temporary files.

Key workflow
1. Visitor pastes a valid YouTube link.
2. System validates the URL and, when valid, fetches the stream.
3. User chooses between MP4 (1080p) or audio-only MP3.
4. Optional: a quick thumbnail or short clip preview before they confirm the download.
5. Finished file is served through HTTPS, then any temp artifacts are wiped.

What matters most to me is a clean, lightweight UI, solid error handling for bad or unsupported links, and overall speed. If you can suggest a reliable extraction library (e.g., yt-dl-python, yt-dlp, or a custom microservice) and pair it with a simple front end—React, Vue, or plain HTML/JS are all fine—please outline that in your proposal.

Deliverable
• Complete source code (frontend + backend) ready to deploy on a standard VPS or serverless stack, with setup instructions.
• Brief README explaining how to add more resolutions or formats later.
• Demo link or short screen capture proving fast turnaround and correct file output.

Let me know if you’ve built something similar and how quickly you can get an MVP online.