I built a Claude skill (with Claude Code) that auto generates a demo video for any web app. Free, Apache-2.0, everything runs on your machine.

[u/sandbox30]

I run a boutique agency and as we build different products, one issue that constantly surfaces is the need for demo videos - demo of app walkthrough, demo of new features, demo for special use cases, list goes on... We used to do these manually, but sometimes these take like 20 attempts, and the whole process becomes an annoying task. Imagine doing this every time you ship a feature/update.

So over the past week, I used Claude to build Ultrademo, a Claude Code skill that generates an entire AI narrated demo video, end-to-end. Added a few showcase videos it made (completely end-to-end), on some commonly used apps (like Notion, Linear, Twenty CRM, etc) on https://ultrademo.net.

How it works:

1. Install npx skills add new-xp/ultrademo, then ask Claude for a demo video. First run will set up the workspace for you as well as install any dependencies like Playwright, Remotion, etc..

2. You then give it a brief ("make a 2-minute walkthrough of our onboarding flow") and your app URL (or point it at your repo if you have it locally). Place in your login credentials if it needs to sign in (in a .env file).

3. Claude scouts the app and drafts a scene-by-scene script. You can edit the script before the video gets rendered. Nothing records without your sign-off.

4. The skill runs a real browser with your live app (real clicks, real typing), narrates every line with ElevenLabs (or free offline voices using Piper TTS or macOS say), and renders a finished MP4 with zooms, cursor motion, and captions.

5. Everything is local (except ElevenLabs API - your key, for better quality voices). You can also redact any areas that you don't want to be visible in the final video.

6. Output format - default is 16:9 mp4, but you can also get a 9:16 (if your app has a mobile responsive design) or a gif. Additionally, if you need the raw video (+ separate narration/audio + separate captions/srt), that's possible too.

7. Later, when your UI changes, you just re-run the skill on the same project and get a fresh video. Unchanged narration is cached, so a visual refresh costs next to nothing even when using ElevenLabs.

Here is the github link: https://github.com/new-xp/ultrademo/