Testing out Alloy for vibe-prototyping

A step forward for both usability and usefulness of these tools.

I’ve been using Alloy for a few days now, and it’s a very effective way to build prototypes. I’ve been a very loyal Bolt user for months now, but I could see myself switching to Alloy full-time.

The premise of Alloy is pretty simple. Their insight is that, most of the “vibe coding” or “vibe prototyping” products, like Bolt, Lovable and Make fall down in one key area, they don’t really know what your product looks like. Most of us use screenshots to give them enough context. I know there are probably ways to inject a design system, or component library, but for the most part, I don’t see many people doing this, I certainly am not.

Alloy has a different approach which is quite clever.

The entry point is a browser extension. You look at a screen in your app, use the extension to “capture” the app, and then start prompting from there. Unsurprisingly, it’s more effective at having prototypes and concepts “look and feel” like your existing product, which I find helps in internal discussions and getting to alignment.

Of course, this isn’t as useful for blue-sky opportunities, or if the app doesn’t exist yet, but for actual PMs, doing actual work in an existing product, this feels like a big leap forward for UX and usability.

Here’s a quick demo, or a Loom link if you prefer that.