HackerTube: Karpathy built a YouTube alternative with Claude in 2 hours

On October 31, Andrej Karpathy launched HackerTube, a YouTube-style site built from the videos people recommended in Hacker News comments. As he writes on his blog, the whole thing was built by Claude Opus 5.5 in Claude Code in about 2 hours, and the Hacker News thread hit number one with over 1,100 points and 345 comments.

What is HackerTube?

It’s an alternative to the YouTube home page, built from what HN readers have been recommending to each other. Inside you’ll find:

1. 6,454 videos from 2007–2026, split into 150 topics.
2. Its own “For You” feed with no account needed, because the state lives in your browser.
3. Thumbnails taken from the middle of the video (“the 50% thumbnail”, in his words) instead of the ones uploaded by creators, so less clickbait.
4. Keyboard shortcuts and a “Longs” filter for long-form content.
5. A data export, so anyone can hand it to their own AI agent and build their own version.

The idea came out of frustration. Karpathy describes a Friday evening on YouTube as an “enshittified wall of slop” and says the algorithm “definitely does not work” for him. The next morning he asked Claude for an alternative.

How was HackerTube built?

This is where it gets interesting. According to the post, Karpathy defaults to Opus 5.5 at Medium effort in the Claude Code desktop app on his Mac. The process went like this:

1. Claude downloaded a Hacker News comments dataset from Hugging Face.
2. Using a Workflow (a Claude Code feature), it ran Sonnet over the comments, which filtered out spam and narrowed the set down to about 40,000 comments recommending a YouTube video.
3. From there came the video list, a YouTube-style interface, deployment to a VPS, and finally security hardening and optimization.

Karpathy did very little by hand. In the HN comments he says he didn’t touch anything himself and only talked to Claude (“I only talked to Claude the whole project”). The exceptions were a YouTube API key in Google Cloud, the domain, a DNS record, and spinning up the VPS. On his blog he adds that he no longer does “anything resembling traditional engineering”.

Why is everyone talking about it?

First, the author. Karpathy is an OpenAI co-founder and former head of AI at Tesla, and his weekend projects regularly set the agenda for the AI internet (he’s the one who popularized “vibe coding”). Since May 2026 he has been on the pretraining team at Anthropic, so he is praising his own company’s tool – worth keeping in mind when reading his enthusiasm.

Second, speed. About 2 hours passed from idea to a working, deployed site, with a data pipeline over tens of thousands of comments along the way.

Third, the way he works. Karpathy writes in the comments that his prompts keep getting shorter and “dumber”, because the model gets what he means anyway. Sometimes he just types “check recent cyber stuff” and Claude launches several subagents on its own. He adds, though, that he only trusts Opus 5.5 and newer models this much (“The thing is beast mode”).

HN readers like the result too: they praise the curation and the fact that each video shows the HN comments that recommended it. Karpathy kept adding features during the discussion, such as sorting by date via “Filter”.

What to watch out for

First, YouTube’s terms of service. One commenter described how Google forced a similar project offline. HackerTube uses embedded YouTube players, so ads still reach creators, but the risk remains.

Second, expectations. Some commenters admit that their AI agents give up halfway or contradict themselves, and doubt they could repeat this in 2 hours. Karpathy is an extreme case: he knows exactly what he wants and he knows the data.

Third, costs. The post doesn’t say how many tokens the project used. If we want to try something similar, it’s worth watching our limits, because Claude Code can burn through tokens in non-obvious ways.

FAQ

Is HackerTube free?

Yes, hackertube.org works without an account or login. Videos play through the embedded YouTube player.

Can I build my own HackerTube?

Karpathy provides the data export precisely so you can hand it to your own AI agent and build your own version. If you’re just getting started with Claude Code, I covered the basics in my tutorial.

Which model did Karpathy use?

Claude Opus 5.5 at Medium effort in Claude Code, plus Sonnet running in a Workflow to filter the HN comments.

How long did it take to build HackerTube?

According to Karpathy’s post, about 2 hours, from downloading the data to a deployed site.