Remember WebContainers? It’s the WebAssembly-based “microoperating system” that can run Vite operations and the entire Node.js ecosystem in the browser. The StackBlitz team built WebContainers to power their in-browser IDE, but it often felt like the technology was still searching for a killer use case—until now. That’s because StackBlitz just released bolt.new, an AI-powered development sandbox that Eric Simons described during ViteConf as “like if Claude or ChatGPT had a baby with StackBlitz.”

I’ll try not to imagine it too vividly, but based on the overwhelmingly positive reviews so far, I’m guessing it’s working – dozens of developers describe it as a combination of v0, Claude, Cursor, and Replit. How Bolt is different: Existing AI code tools can often run some basic JavaScript/HTML/CSS in the browser, but for more complex projects, you need to copy and paste the code to a local environment. But not Bolt. By using WebContainers, you can request, run, edit, and deploy entire web applications, all from the browser. Here’s what it looks like:

• You can ask bolt.new to build a production-ready multi-page app with a specific backend and database, using any technology stack you want (e.g. “Build a personal blog using Astro, Tailwind, and shadcn”).
• Unlike other tools, Bolt can install and run relevant npm packages and libraries, interact with third-party APIs, and run Node servers.
• You can manually edit the code it generates via an in-browser editor, or have Bolt resolve errors for you . This is unique to Bolt, because it integrates AI into all levels of WebContainers (not just the CodeGen step).
• You can deploy to production from chat via Netlify, no login required.

There’s a lot more we could go over here, but Eric’s demo is pretty wild. In closing: From the outside, it wasn’t always clear whether StackBlitz would ever see a significant return on investment over the 5+ years they’ve spent developing WebContainers. But suddenly it looks like they might be uniquely positioned to help developers leverage AI to build legitimate FullStack applications.

I hope this has been helpful and/or taught you something new!

@khriztianmoreno 🚀