Karpathy launches HackerTube, a Claude-built catalog of 6,454 videos

Andrej Karpathy released HackerTube on October 31, turning YouTube links from Hacker News discussions into a separate video-discovery site. Visitors can find videos by subject and follow the discussions behind them. He says he built it in roughly two hours with Opus 5.5 in Claude Code’s Mac desktop app, using his default Medium reasoning effort.

Karpathy says Claude handled development and deployment, while he created the metadata API key, started the server and bought the domain. The site replaces uploader-selected thumbnails with a frame from the middle of each video.

He reported 504 million input tokens and 7.6 million output tokens, with 90% of input cached. He attributed over 90% of the processing to Sonnet comment labeling. On a subscription, he had Claude total the usage.

The site says its collection started with videos linked by at least three different people across at least three different months. Sonnet classified mentions using the comment and discussion title, separating recommendations, references, jokes and criticism. At most 20 mentions are retained per video.

Public statistics list 6,454 videos, 39,834 retained mentions and 150 topics across 16 areas, covering 2007–2026. These describe the collection, rather than its viewing audience.

1,658 videos have zero positive recommenders recorded

AI Ping counted every record in the public video file on November 2. Of the collection, 1,658 videos—about 25.7%—had zero positive recommenders recorded. This counts the export’s AI-generated labels, not video quality.

The file also labels 1,448 entries as talks, 1,091 as explainers and 827 as demonstrations. Its scope extends beyond technical lectures, including 567 entries labeled comedy and 187 labeled music. The 6,454 records have distinct video IDs.

Karpathy described adding duration, upload-date and content-type filters. Visitors can sort by the latest Hacker News recommendation or find hour-plus videos in Longs. It also opens up to 50 videos as a temporary YouTube playlist. The Hidden gems filter selects videos valued on Hacker News with under 100,000 YouTube views.

According to the site, likes, viewing history and watch-later selections stay in the browser without an account. Its home feed mixes similar videos and videos recommended by the same Hacker News users. Video pages include actual comments and links to the original discussions. Playback uses YouTube’s privacy-enhanced embed.

The October 31 export manifest lists files for 6,454 video records, 39,834 classified mentions and 150 topic categories. It also includes related-video entries for 3,778 videos and search data. The full ZIP is about 17.8MB and can support other interfaces or recommendation tools.

The ranking counts distinct months with recommendations, giving extra weight to months with strong recommendations. The documentation warns that model-written summaries and classifications can contain errors. Retained comments are truncated at 1,500 characters, and the same talk can appear under different video IDs.

The data uses ODC-By 1.0 with attribution to HackerTube and its source Hacker News dataset. YouTube metadata, including view and like counts, durations and publication dates, is excluded and requires a separate lookup using the video IDs. Karpathy said in the discussion that he had not published the server code.