Bolt performance

Large Bundle Size - App Loads Slowly

Your JavaScript bundle is very large (over 500KB), making the app slow to load. First Contentful Paint takes several seconds even on good connections.

Users on slow networks experience long loading times.

Error Messages You Might See

Bundle size 750KB (over limit) First Contentful Paint 8 seconds Large Cumulative Layout Shift Slow interaction to Next Paint
Bundle size 750KB (over limit)First Contentful Paint 8 secondsLarge Cumulative Layout ShiftSlow interaction to Next Paint

Common Causes

  1. Importing entire library when only small part needed
  2. Large image assets embedded in bundle instead of loaded separately
  3. Unused code not being tree-shaken by build tool
  4. Moment.js or similar heavy date libraries (use date-fns, dayjs instead)
  5. Loading all routes upfront instead of code splitting by route

How to Fix It

Use tree-shakeable imports: import { map } from 'lodash-es' not import lodash

Lazy load heavy components: const Component = dynamic(() => import('@/components/Heavy'))

Replace heavy libraries: moment.js -> date-fns or dayjs, @apollo/client -> urql

Optimize images: use next/image, convert to WebP, serve appropriate sizes

Enable code splitting in Next.js config (automatic for routes)

Real developers can help you.

Basel Issmail Basel Issmail ’m a Senior Full-Stack Developer and Tech Lead with experience designing and building scalable web platforms. I work across the full development lifecycle, from translating business requirements into technical architecture to delivering reliable production systems. My work focuses on modern web technologies, including TypeScript, Angular, Node.js, and cloud-based architectures. I enjoy solving complex technical problems and helping teams turn product ideas and prototypes into working platforms that can grow and scale. In addition to development, I often collaborate closely with product managers, business analysts, designers, and QA teams to ensure that solutions align with both technical and business goals. I enjoy working with startups and product teams where I can contribute both as a hands-on engineer and as a technical partner in designing and delivering impactful software. Luca Liberati Luca Liberati I work on monoliths and microservices, backends and frontends, manage K8s clusters and love to design apps architecture 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. 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. PawelPloszaj PawelPloszaj I'm fronted developer with 10+ years of experience with big projects. I have small backend background too 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. 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. 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. 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 Jaime Orts-Caroff Jaime Orts-Caroff I'm a Senior Android developer, open to work in various fields

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Frequently Asked Questions

What's a good target bundle size?

JavaScript: <200KB. With gzip: <50KB. For comparison, heavy frameworks are ~200KB

How do I check actual bundle size?

npm run build shows Next.js Size. Use webpack-bundle-analyzer for detailed breakdown

What about image sizes?

Use next/image for automatic optimization. Aim for <100KB total images, <30KB per image

Related Bolt Issues

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