Breaking

Karpathy Reports Using Claude to Build a YouTube Alternative in About Two Hours

November 3, 2026 at 09:32 EST

Software Dev & Coding
Foundation Models

Andrej Karpathy reportedly used Anthropic's Claude to filter 43 million Hacker News comments down to 6,454 videos, then built a YouTube alternative in roughly two hours with the Opus 5.5 model.

AI-assisted development · Reported, unverified

From 43 million comments to 6,454 videos, then a prototype in about two hours

A reported weekend project says Claude sorted a very large forum comment archive down to a short list of video links, and a YouTube-style app was then assembled in roughly two hours. The details have not been independently confirmed.

43M

Hacker News comments in the input pool

6,454

Videos identified by the filtering step

~2 hrs

Reported time to build the app

Input vs. output, drawn to scale

Each block is a 1/30 share of the input pool. The 6,454 videos are about 0.015% of the input, too small to draw at true height, so they are shown as a single minimum-height block.

43M comments

6,454 videos

(not to scale)

The reported pipeline

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