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.

Bastien Labelle Bastien Labelle Full stack dev w/ 20+ years of experience Jaime Orts-Caroff Jaime Orts-Caroff I'm a Senior Android developer, open to work in various fields AUXLE AUXLE I am a Full Stack Developer experienced in building Websites, Web apps and Cross Platform Mobile Apps for Startups and Companies. ISHANTDEEP SINGH ISHANTDEEP SINGH Senior Software Engineer with 7+ years of experience in React, JavaScript, TypeScript, Next.js, and Node.js. I’ve also worked as a tech lead for startups, owning end-to-end technical execution including architecture, development, scaling, and delivery. I bring a strong mix of hands-on coding, product thinking, and technical leadership, and I’m comfortable building products from scratch as well as improving and scaling existing systems. Simon A. Simon A. I'm a backend developer building APIs, emulators, and interactive game systems. Professionally, I've developed Java/Spring reporting solutions, managed relational and NoSQL databases, and implemented CI/CD workflows. Antriksh Narang Antriksh Narang 5 years+ Experienced Dev (Specially in Web Development), can help in python, javascript, react, next.js and full stack web dev technologies. Yovel Cohen Yovel Cohen I got a lot of experience in building Long-horizon AI Agents in production, Backend apps that scale to millions of users and frontend knowledge as well. Richard McSorley Richard McSorley Full-Stack Software Engineer with 8+ years building high-performance applications for enterprise clients. Shipped production systems at Walmart (4,000+ stores), Cigna (20M+ users), and Arkansas Blue Cross. 5 patents in retail/supply chain tech. Currently focused on AI integrations, automation tools, and TypeScript-first architectures. 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.

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

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