Web Worker

The VM runs a single-threaded cooperative scheduler; on the main thread it can block the UI. NanoWorkerClient hosts it in a Web Worker with the same API, just async.

Create a worker-hosted VM

import { createNanoWorker } from "@userland-run/nano-sdk";

const client = await createNanoWorker(config);

NanoWorkerClient mirrors Nano — run / exec / shExec / node, shell(), scripting(), nodeRuntime(), serve mode, interactive stdin, cancel / destroy — over a message channel.

Async filesystem

client.fs has the same methods as Vfs, but every call is a promise (an RPC round-trip to the worker).

await client.fs.writeFile("/app/main.js", src);
const out = await client.fs.readText("/app/out.txt");

When to use it

• Any UI that must stay responsive during long runs.
• Serving and streaming output.
• Cold Node boots, which are CPU-heavy.