StackBlitz Rate Limits

Overview

WebContainer resource limits: memory, CPU, file system size, process count.

Instructions

Step 1: WebContainer Resource Limits

Resource	Limit	Notes
Memory	~2GB	Shared with browser tab
File system	Ephemeral, in-memory	Lost on page refresh
Processes	Multiple concurrent	Each consumes memory
Network	HTTP only	No raw TCP/UDP sockets
npm packages	Most work	Native addons not supported

Step 2: Handle Memory Pressure

// Monitor memory usage inside WebContainer
const proc = await wc.spawn('node', ['-e', `
  setInterval(() => {
    const mem = process.memoryUsage();
    const mbUsed = Math.round(mem.heapUsed / 1024 / 1024);
    if (mbUsed > 500) console.warn('High memory: ' + mbUsed + 'MB');
  }, 5000);
`]);

Step 3: Optimize File System Size

// Mount only essential files -- skip test files, docs, etc.
const productionFiles: FileSystemTree = {
  'package.json': { file: { contents: minimalPackageJson } },
  src: { directory: { /* only source files */ } },
  // Skip: tests/, docs/, .git/, large assets
};
await wc.mount(productionFiles);

Error Handling

Issue	Cause	Solution
Tab crashes	OOM	Reduce mounted files, fewer deps
Slow npm install	Large deps	Use --prefer-offline, fewer packages
Process killed	Memory limit	Monitor with memoryUsage()

Resources

• WebContainer Guides

Next Steps

For security, see stackblitz-security-basics.