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.

Omar Faruk Omar Faruk As a Product Engineer at Klasio, I contributed to end-to-end product development, focusing on scalability, performance, and user experience. My work spanned building and refining core features, developing dynamic website templates, integrating secure and reliable payment gateways, and optimizing the overall system architecture. I played a key role in creating a scalable and maintainable platform to support educators and learners globally. I'm enthusiastic about embracing new challenges and making meaningful contributions. Dor Yaloz Dor Yaloz SW engineer with 6+ years of experience, I worked with React/Node/Python did projects with React+Capacitor.js for ios Supabase expert Jaime Orts-Caroff Jaime Orts-Caroff I'm a Senior Android developer, open to work in various fields Victor Denisov Victor Denisov Developer AUXLE AUXLE I am a Full Stack Developer experienced in building Websites, Web apps and Cross Platform Mobile Apps for Startups and Companies. Stanislav Prigodich Stanislav Prigodich 15+ years building iOS and web apps at startups and enterprise companies. I want to use that experience to help builders ship real products - when something breaks, I'm here to fix it. Luca Liberati Luca Liberati I work on monoliths and microservices, backends and frontends, manage K8s clusters and love to design apps architecture Tejas Chokhawala Tejas Chokhawala Full-stack engineer with 5 years experience building production web apps using React, Next.js and TypeScript. Focused on performance, clean architecture and shipping fast. Experienced with Supabase/Postgres backends, Stripe billing, and building AI-assisted developer tools. legrab legrab I'll fill this later Jared Hasson Jared Hasson Full time lead founding dev at a cyber security saas startup, with 10 yoe and a bachelor's in CS. Building & debugging software products is what I've spent my time on for forever

You don't need to be technical. Just describe what's wrong and a verified developer will handle the rest.

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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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