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.

Rudra Bhikadiya Rudra Bhikadiya I build and fix web apps across Next.js, Node.js, and DBs. Comfortable jumping into messy code, broken APIs, and mysterious bugs. If your project works in theory but not in reality, I help close that gap. Franck Plazanet Franck Plazanet I am a Strategic Engineering Leader with over 8 years of experience building high-availability enterprise systems and scaling high-performing technical teams. My focus is on bridging the gap between complex technology and business growth. Core Expertise: 🚀 Leadership: Managing and coaching teams of 15+ engineers, fostering a culture of accountability and continuous improvement. 🏗️ Architecture: Enterprise Core Systems, Multi-system Integration (ERP/API/ETL), and Core Database Structure. ☁️ Cloud & Scale: AWS Expert; architected systems handling 10B+ monthly requests and managing 100k+ SKUs. 📈 Business Impact: Aligning tech strategy with P&L goals to drive $70k+ in monthly recurring revenue. I thrive on "out-of-the-box" thinking to solve complex technical bottlenecks and am always looking for ways to use automation to improve business productivity. 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. Krishna Sai Kuncha Krishna Sai Kuncha Experienced Professional Full stack Developer with 8+ years of experience across react, python, js, ts, golang and react-native. Developed inhouse websearch tooling for AI before websearch was solved : ) Jen Jacobsen Jen Jacobsen I’m a Full-Stack Developer with over 10 years of experience building modern web and mobile applications. I enjoy working across the full product lifecycle — turning ideas into real, well-built products that are intuitive for users and scalable for businesses. I particularly enjoy building mobile apps, modern web platforms, and solving complex technical problems in a way that keeps systems clean, reliable, and easy to maintain. 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. Matthew Jordan Matthew Jordan I've been working at a large software company named Kainos for 2 years, and mainly specialise in Platform Engineering. I regularly enjoy working on software products outside of work, and I'm a huge fan of game development using Unity. I personally enjoy Python & C# in my spare time, but I also specialise in multiple different platform-related technologies from my day job. AUXLE AUXLE I am a Full Stack Developer experienced in building Websites, Web apps and Cross Platform Mobile Apps for Startups and Companies. 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. BurnHavoc BurnHavoc Been around fixing other peoples code for 20 years.

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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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