Field Notes

ClassBlur: a new web tool in minutes

Claude and I built a useful web app in minutes

I’m in a WhatsApp group focused on Educational Technology and today, at about 1:40 in the afternoon, my friend Binyomin posted:

looking for a (pref free) easy to use tool to blur faces in a short video. i see a few tools come up on a google search, but anyone have any experience and specific recommendations? tia.

I jumped into iTerm, opened a new tab, created a directory, invoked Claude, and asked for help. I have a day job, so I only ever interacted with the AI while on hold or waiting for a meeting to start. So, while the actual development only took about 20 minutes, I didn’t push the repo and publish the tool online until about 5:40 pm.

The result is ClassBlur, a tool which will blur out faces in any video you give it. I presume there is a max length, but I don’t know what it is.

All I told Claude was:

"OK, here is the goal: I want to build a simple web app to blurr faces in video so that educators can share classroom video on the web. The tool should:

  1. Accept uploads from common smartphone video formats
  2. Identify faces of children
  3. blur them in a new video file made available for download

UNBREAKABLE RULES:

  • no video is saved ever.
  • no data of any kind is saved ever.
  • these rules are made clear"

The rest of the time was spent testing, connecting to GitHub, and creating an account to host it at Netlify. I honestly spent more time granting Claude permission than I did troubleshooting.

I’m still having a blast with this stuff. :)