An in-browser Workers development environment

Cloudflare is kicking off Platform Week with a focus on the developer experience. The company's latest partnership, with StackBlitz, brings a new twist to working with Workers: the Wrangler CLI can now run directly in your browser via WebContainers, StackBlitz’s WebAssembly-based operating system. Each time you load a page, you get a fresh development environment with all dependencies installed—no local setup required.

WebContainers effectively boot a full operating system inside your browser tab, complete with a file system, multi-process and multi-threading support, and a virtualized TCP network stack built on ServiceWorkers. Because everything runs locally in the tab, there is no remote server to wait on when spinning up a project. Currently, this works only in Chromium-based browsers.

This builds on the announcements around the general availability of the new Wrangler version. The updated tooling makes it easier to start developing with Workers, and running it in a WebContainer means the entire setup process is reduced to opening a URL. You can try it immediately by navigating to https://workers.new/typescript.

The underlying WebContainer technology is open for inspection. StackBlitz has published an introduction blog post on the architecture, and a working group maintains a GitHub repository (https://github.com/stackblitz/webcontainer-core) for ongoing collaboration.

Templates for instant starts

One practical outcome of this partnership is faster access to documentation examples and tutorials. Instead of waiting for a remote container to spin up, developers can embed or link full code projects that boot instantly. Cloudflare and StackBlitz have prepared templates to demonstrate the workflow:

  • https://workers.new/router
  • https://workers.new/durable-objects
  • https://workers.new/typescript

Each of these URLs launches a local Workers application environment in the browser.

What is still on the roadmap

The in-browser Wrangler currently supports local development mode. Cloudflare and StackBlitz are working together to extend the experience to the full developer lifecycle. The next milestones involve enabling authentication so that developers can deploy to the edge, debug, and tail logs for published Workers—all without leaving the browser tab.