Bolt performance

WebContainer Slow Startup - App Takes Time to Boot

Your Bolt WebContainer takes a long time to start - 30+ seconds before seeing the dev server running. Development workflow is slow due to startup delays.

This happens consistently, making every new session wait.

Error Messages You Might See

WebContainer initialization timeout Node modules taking 2+ minutes to install Dev server not starting after 5 minutes Spinning loader never completes
WebContainer initialization timeoutNode modules taking 2+ minutes to installDev server not starting after 5 minutesSpinning loader never completes

Common Causes

  1. Large node_modules size slowing file system
  2. Many dependencies causing npm install to take forever
  3. Post-install scripts (build, setup) in package.json taking time
  4. WebContainer downloading dependencies on first run
  5. Heavy TypeScript compilation on startup

How to Fix It

Minimize dependencies: remove unused packages, audit with npm ls

Use npm ci instead of npm install for faster, deterministic installs

Remove unnecessary postinstall scripts or make them optional

Pre-compile TypeScript if possible, or disable strict mode in dev

Clear npm cache in Bolt: might be cached from previous run

Consider using pnpm instead of npm (faster for monorepos)

Real developers can help you.

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Frequently Asked Questions

Why is WebContainer slow on first run?

Downloading node_modules, dependencies, and setting up environment. Subsequent runs are cached

Should I commit node_modules?

No, Bolt installs fresh. Keep package-lock.json committed for reproducible builds

How do I speed up dependencies?

Use pnpm (faster), audit and remove unused packages, use npm ci instead of install

Related Bolt Issues

Can't fix it yourself?
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