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.

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. Meïr Ankri Meïr Ankri Full-stack developer specializing in React / Next.js / Node.js with 6+ years of experience. I've worked across various sectors including automotive (Reezocar/Société Générale), healthcare (Medical Link SaaS), and e-commerce (Glasman). I build web apps end-to-end, from architecture to production, with a focus on scalability, performance, and code quality. I also mentor junior developers and contribute to technical decisions and code reviews. Matthew Butler Matthew Butler Systems Development Engineer @ Amazon Web Services prajwalfullstack prajwalfullstack Hi Im a full stack developer, a vibe coded MVP to Market ready product, I'm here to help Sage Fulcher Sage Fulcher Hey I'm Sage! Im a Boston area software engineer who grew up in South Florida. Ive worked at a ton of cool places like a telehealth kidney care startup that took part in a billion dollar merger (Cricket health/Interwell health), a boutique design agency where I got to work on a ton of exciting startups including a photography education app, a collegiate Esports league and more (Philosophie), a data analytics as a service startup in Cambridge (MA) as well as at Phillips and MIT Lincoln Lab where I designed and developed novel network security visualizations and analytics. I've been writing code and furiously devoted to using computers to make people’s lives easier for about 17 years. My degree is in making computers make pretty lights and sounds. Outside of work I love hip hop, the Celtics, professional wrestling, magic the gathering, photography, drumming, and guitars (both making and playing them) hanson1014 hanson1014 Full-stack developer experienced in fixing and deploying AI-generated apps from Lovable, Bolt.new, Cursor, and Replit. I specialize in debugging Supabase integration issues (auth flows, RLS policies, database connections), fixing broken deployments, resolving routing/blank screen problems, and cleaning up messy React/Vite codebases. I also build production apps with the Claude API and have shipped a Mac desktop dev tool (Nexterm from scratch. Based in Hong Kong, fast turnaround. Victor Denisov Victor Denisov Developer Milan Surelia Milan Surelia Milan Surelia is a Mobile App Developer with 5+ years of experience crafting scalable, cross-platform apps at 7Span and Meticha. At 7Span, he engineers feature-rich Flutter apps with smooth performance and modern UI. As the Co-Founder of Meticha, he builds open-source tools and developer-focused products that solve real-world problems. Expertise: 💡 Developing cross-platform apps using Flutter, Dart, and Jetpack Compose for Android, iOS, and Web. 🖋️ Sharing insights through technical writing, blogging, and open-source contributions. 🤝 Collaborating closely with designers, PMs, and developers to build seamless mobile experiences. Notable Achievements: 🎯 Revamped the Vepaar app into Vepaar Store & CRM with a 2x performance boost and smoother UX. 🚀 Launched Compose101 — a Jetpack Compose starter kit to speed up Android development. 🌟 Open source contributions on Github & StackOverflow for Flutter & Dart 🎖️ Worked on improving app performance and user experience with smart solutions. Milan is always happy to connect, work on new ideas, and explore the latest in technology. Bastien Labelle Bastien Labelle Full stack dev w/ 20+ years of experience Prakash Prajapati Prakash Prajapati I’m a Senior Python Developer specializing in building secure, scalable, and highly available systems. I work primarily with Python, Django, FastAPI, Docker, PostgreSQL, and modern AI tooling such as PydanticAI, focusing on clean architecture, strong design principles, and reliable DevOps practices. I enjoy solving complex engineering problems and designing systems that are maintainable, resilient, and built to scale.

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

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