name: stackblitz-install-auth description: 'Install the WebContainer API and configure StackBlitz SDK for browser-based Node.js.

Use when setting up WebContainers, embedding StackBlitz projects,

or initializing the @stackblitz/sdk package.

Trigger: "install stackblitz", "setup webcontainers", "stackblitz SDK".

' allowed-tools: Read, Write, Edit, Bash(npm:*), Grep version: 1.0.0 license: MIT author: Jeremy Longshore jeremy@intentsolutions.io tags:

• saas
• ide
• webcontainers
• stackblitz compatibility: Designed for Claude Code

StackBlitz Install & Auth

Overview

Set up the WebContainer API for running Node.js in the browser, or the StackBlitz SDK for embedding interactive code editors. WebContainers require no auth -- they run entirely client-side. The StackBlitz SDK is for embedding projects from stackblitz.com.

Prerequisites

• Node.js 18+ for build tooling
• Modern browser with SharedArrayBuffer support (requires HTTPS + COOP/COEP headers)

Instructions

Step 1: Install WebContainer API

npm install @webcontainer/api

Step 2: Install StackBlitz SDK (for embedding)

npm install @stackblitz/sdk

Step 3: Configure Required HTTP Headers

WebContainers require cross-origin isolation. Add these headers to your server:

// Express middleware
app.use((req, res, next) => {
  res.setHeader('Cross-Origin-Embedder-Policy', 'require-corp');
  res.setHeader('Cross-Origin-Opener-Policy', 'same-origin');
  next();
});

// Vite config
export default defineConfig({
  server: {
    headers: {
      'Cross-Origin-Embedder-Policy': 'require-corp',
      'Cross-Origin-Opener-Policy': 'same-origin',
    },
  },
});

Step 4: Verify WebContainer Boot

import { WebContainer } from '@webcontainer/api';

const wc = await WebContainer.boot();
console.log('WebContainer booted successfully');

// Verify filesystem works
await wc.mount({ 'test.txt': { file: { contents: 'Hello WebContainers!' } } });
const content = await wc.fs.readFile('/test.txt', 'utf-8');
console.log(`File content: ${content}`);

Output

WebContainer booted successfully
File content: Hello WebContainers!

Error Handling

Resources

• WebContainer API Docs
• WebContainer Quickstart
• StackBlitz SDK

Next Steps

Proceed to stackblitz-hello-world for your first WebContainer project.