Ep #31: Mastering Large-Scale System Design: Best Practices Across the Stack

A comprehensive guide to designing scalable, resilient, and secure systems - from frontend to backend and beyond.

Ep #31: Breaking the complex System Design Components

By Amit Raghuvanshi | The Architect’s Notebook
🗓️ Aug 28, 2025 · Premium Post ·

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If someone asks you, “What are the best practices to follow when designing a system end to end?” It’s usually not easy to answer on the spot. That’s why I’ve put together this comprehensive list of best practices across the stack.

You can treat this as a reference guide: check it against your current project and see if these practices are being followed. It’s not just theory - these are the principles engineers rely on when building real-world, large-scale systems that serve millions of users.

The goal here is to keep things easy to understand, practical, and to the point. Let’s go through each component, from the frontend to the backend, databases, caching, messaging, security, monitoring, and DevOps.

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1. Frontend (Client-side)

Components

Web app, Mobile app, SPA/MPA, CDN

Best Practices:

• Component Architecture:

  • Break the UI into small, reusable, and composable components that each encapsulate a single responsibility.

  • Adopting atomic or feature-first¹ structures makes the interface easier to scale, test, and maintain.

  • Use smart (container) and dumb (presentational) component² patterns for clear separation of concerns.

• Performance & Load

  • CDN for Static Assets: Serve images, CSS, JS, and fonts via CDN to reduce latency, minimize load on core servers, and speed up delivery worldwide.

  • Minify & Compress: Shrink JS/CSS files using minification and user GZIP/Brotli compression to reduce transfer sizes and improve page speed.

  • Lazy Loading³: Load images and non-critical resources only as the user scrolls or requests them (reducing initial load time).

  • Code Splitting⁴: Break large JS bundles into smaller chunks that load only when needed, speeding up initial load and navigation.

  • Use performance monitoring tools (such as Lighthouse⁵ or Sentry⁶) for continuous optimization and observability.

• Scalability

  • Stateless UI: Ensure the frontend can reload or rerender at any time without relying on client-side sessions for sensitive data (it improves scalability and security).

  • Client-Side Caching: Use ETag HTTP headers⁷ or service workers⁸ for effective browser caching; avoids redundant server requests and improves responsiveness.

• UX & Reliability

  • Graceful Degradation/Offline: Design the UI to handle slow/no network gracefully, providing fallback content or offline support using service workers.

  • Responsive UI: Make layouts flexible across device sizes and orientations ensuring consistent experiences.

  • Error Handling & Retry: Inform users about errors clearly and automatically retry safe operations to enhance reliability.

  • Design Systems & Consistency: Develop a shared design system or component library to enforce visual and UX consistency. Establish code and folder organization standards across teams to ease collaboration and onboarding.

• Security

  • Sanitize User Input: Filter/escape all user-generated content to prevent cross-site scripting (XSS)⁹ attacks.

  • HTTPS & Secure Cookies: Enforce HTTPS for all traffic and use cookies with Secure and HttpOnly¹⁰ flags for session data.

  • CSP Headers: Use strict Content Security Policy headers¹¹ to block unauthorized scripts and reduce XSS risk.

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