For developers who need to test a small app, check out a pull request, prototype a new API, or reproduce a bug, the friction is always the same: messing with a local setup, provisioning a whole virtual machine, or writing a Dockerfile just for a quick task that needs a server environment. It should be as simple as opening a browser tab.
The solution is Stacknow: a complete Linux server and IDE that runs entirely inside your browser, powered by WebAssembly.
When a sandbox is launched, a remote server isn't provisioned. Instead, a full Linux userspace boots directly on your machine inside the browser's Wasm runtime. This provides:
Instant Startup: Loads in seconds. No remote machine to provision.
Zero Latency: It’s as responsive as a native app because it is one, just compiled to Wasm.
Absolute Security: Trapped within the browser's security sandbox with no access to local files or network.
True Ephemerality: The filesystem lives in-memory. Close the tab, and it’s gone.
So, how does a server run when the WebAssembly System Interface (WASI) has no networking stack?
A custom networking layer was built that tunnels traffic over UNIX sockets. Here’s how it works: instead of an app listening on localhost:3000, it listens on a specific UNIX socket path (e.g., /tmp/stacknow.sock). The runtime detects this, automatically pipes all data from that socket to an edge network, and exposes it on a secure public URL. Because all traffic is proxied through the Stacknow network, your server works just like a VPS—there are no CORS restrictions to worry about.
The entire IDE is built on this principle. The file explorer, terminal, and editor are themselves a server running inside the Wasm sandbox, communicating with the browser UI over this exact same UNIX socket tunnel. When you expose your own Node.js, Python, or Go server, you're using the same battle-tested system that powers the IDE itself.
This unified approach means you can run a server, develop against it with a full IDE, and then instantly share it with the world, all from a single browser tab. This is part of the Pro plan, which also includes persistent storage.
It has been found to be super useful for:
Quickly prototyping back-end services without installing anything.
Creating reproducible server environments for bug reports.
Safely inspecting untrusted code or binaries that need to run as a server.
Technical interviews where candidates need to build and run a small web service.
A free tier is available that lets you spin up ephemeral sandboxes. Feel free to try it out and share your thoughts. What's missing? What would you use it for?
To learn more about the platform's technology and performance, go to https://docs.stacknow.io. To chat with the team, head to https://discord.gg/bYKPzpPrRP.
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