Needs a free YouTube Data API key (one-time, ~2 min): go to Google Cloud → enable YouTube Data API v3, then create an API key and paste it above. The key is stored only in your browser and used to call YouTube directly. Free tier is plenty for browsing.
Add your YouTube API key above, pick Trending now or search a topic, and hit Find viral videos. Results are ranked by a virality score — views weighed against how recently they were posted, so fast-rising clips rise to the top.