Managing WebContainer Resource Limits

v20260423

stackblitz-rate-limits

This guide provides essential knowledge on resource limitations within WebContainer environments (such as memory, CPU, file system size, and process count). It is crucial for developers utilizing the WebContainers API or StackBlitz SDK to understand these constraints. Learn best practices for monitoring memory usage, optimizing mounted file systems by excluding unnecessary assets (like test or documentation folders), and managing dependencies to prevent common issues like Out-Of-Memory (OOM) crashes and slow build times.

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Overview

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.

Info

Category Development

Name stackblitz-rate-limits

Version v20260423

Size 1.99KB

Source jeremylongshore/claude-code-plugins-plus-skills

Updated At 2026-04-28