Andrej Karpathy, OpenAI co-founder and current Anthropic AI researcher, built HackerTube over a weekend using Claude's Opus 5.5 model. Claude filtered 43 million comments from 20 years of Hacker News and distilled them into 6,454 videos that keep getting recommended there. The result is a "significantly better viewing experience" than YouTube's own recommendations, Karpathy writes on X. The site needs no login, shows a single mid-video frame instead of optimized thumbnails, and stores state locally in the browser. Right after, Karpathy built TristanTube, "one-shotted with Claude Code in 3 minutes," with 47,000 videos drawn from a YouTube channel list by Tristan Hume. Karpathy says he let Claude Code handle nearly all the work, from data analysis to server setup. His only manual steps were a Google Cloud API key, a rented server, and buying the domain. Projects that used to take weeks can now be done in a few hours, Karpathy says. Subscribe to THE DECODER for ad-free reading, a weekly AI newsletter, our exclusive "AI Radar" frontier report six times a year, full archive access, and access to our comment section.