All Articles (15 articles)

  • Virtualization and Windowing

    System Design / Frontend System Design 20 min read

    Rendering large lists (1,000+ items) without virtualization creates a DOM tree so large that layout calculations alone can block the main thread for hundreds of milliseconds. Virtualization solves this by rendering only visible items plus a small buffer, keeping DOM node count constant regardless of list size. The trade-off: implementation complexity for consistent O(viewport) rendering performance.

  • Offline-First Architecture

    System Design / Frontend System Design 23 min read

    Building applications that prioritize local data and functionality, treating network connectivity as an enhancement rather than a requirement—the storage APIs, sync strategies, and conflict resolution patterns that power modern collaborative and offline-capable applications.Offline-first inverts the traditional web model: instead of fetching data from servers and caching it locally, data lives locally first and syncs to servers when possible. This article explores the browser APIs that enable this pattern, the sync strategies that keep data consistent, and how production applications like Figma, Notion, and Linear solve these problems at scale.

  • Client State Management

    System Design / Frontend System Design 16 min read

    Choosing the right state management approach requires understanding that “state” is not monolithic—different categories have fundamentally different requirements. Server state needs caching, deduplication, and background sync. UI state needs fast updates and component isolation. Form state needs validation and dirty tracking. Conflating these categories is the root cause of most state management complexity.

  • Real-Time Sync Client

    System Design / Frontend System Design 26 min read

    Client-side architecture for real-time data synchronization: transport protocols, connection management, conflict resolution, and state reconciliation patterns used by Figma, Notion, Discord, and Linear.

  • Multi-Tenant Pluggable Widget Framework

    System Design / Frontend System Design 31 min read

    Designing a frontend framework that hosts third-party extensions—dynamically loaded at runtime based on tenant configurations. This article covers the architectural decisions behind systems like VS Code extensions, Figma plugins, and Shopify embedded apps: module loading strategies (Webpack Module Federation vs SystemJS), sandboxing techniques (iframe, Shadow DOM, Web Workers, WASM), manifest and registry design, the host SDK API contract, and multi-tenant orchestration that resolves widget implementations per user or organization.

  • Bundle Splitting Strategies

    System Design / Frontend System Design 19 min read

    Modern JavaScript applications ship megabytes of code by default. Without bundle splitting, users download, parse, and execute the entire application before seeing anything interactive—regardless of which features they’ll actually use. Bundle splitting transforms monolithic builds into targeted delivery: load the code for the current route immediately, defer everything else until needed. The payoff is substantial—30-60% reduction in initial bundle size translates directly to faster Time to Interactive (TTI) and improved Core Web Vitals.

  • Rendering Strategies

    System Design / Frontend System Design 18 min read

    Choosing between CSR, SSR, SSG, and hybrid rendering is not a binary decision—it’s about matching rendering strategy to content characteristics. Static content benefits from build-time rendering; dynamic, personalized content needs request-time rendering; interactive components need client-side JavaScript. Modern frameworks like Next.js 15, Astro 5, and Nuxt 3 enable mixing strategies within a single application, rendering each route—or even each component—with the optimal approach.

  • Image Loading Optimization

    System Design / Frontend System Design 13 min read

    Client-side strategies for optimizing image delivery: lazy loading, responsive images, modern formats, and Cumulative Layout Shift (CLS) prevention. Covers browser mechanics, priority hints, and real-world implementation patterns.

  • Client Performance Monitoring

    System Design / Frontend System Design 18 min read

    Measuring frontend performance in production requires capturing real user experience data—not just synthetic benchmarks. Lab tools like Lighthouse measure performance under controlled conditions, but users experience your application on varied devices, networks, and contexts. Real User Monitoring (RUM) bridges this gap by collecting performance metrics from actual browser sessions, enabling data-driven optimization where it matters most: in the field.

  • Design a Rich Text Editor

    System Design / Frontend System Design 19 min read

    Building a rich text editor for web applications requires choosing between fundamentally different document models, input handling strategies, and collaboration architectures. This article covers contentEditable vs custom rendering trade-offs, the document models behind ProseMirror, Slate, Lexical, and Quill, transaction-based state management, browser input handling (Input Events Level 2, IME), collaboration patterns (OT vs CRDT), virtualization for large documents, and accessibility requirements.

  • Design an Infinite Feed

    System Design / Frontend System Design 19 min read

    Building infinite scrolling feed interfaces that scale from hundreds to millions of items while maintaining 60fps scroll performance. This article covers pagination strategies, scroll detection, virtualization, state management, and accessibility patterns that power feeds at Twitter, Instagram, and LinkedIn.

  • Design a Drag and Drop System

    System Design / Frontend System Design 26 min read

    Building drag and drop interactions that work across input devices, handle complex reordering scenarios, and maintain accessibility—the browser APIs, architectural patterns, and trade-offs that power production implementations in Trello, Notion, and Figma.Drag and drop appears simple: grab an element, move it, release it. In practice, it requires handling three incompatible input APIs (mouse, touch, pointer), working around significant browser inconsistencies in the HTML5 Drag and Drop API, providing keyboard alternatives for accessibility, and managing visual feedback during the operation. This article covers the underlying browser APIs, the design decisions that differentiate library approaches, and how production applications solve these problems at scale.

  • Design a Form Builder

    System Design / Frontend System Design 20 min read

    Schema-driven form generation systems that render dynamic UIs from declarative definitions. This article covers form schema architectures, validation strategies, state management patterns, and the trade-offs that shape production form builders like Typeform, Google Forms, and enterprise low-code platforms.

  • Design a Data Grid

    System Design / Frontend System Design 19 min read

    High-performance data grids render thousands to millions of rows while maintaining 60fps scrolling and sub-second interactions. This article explores the architectural patterns, virtualization strategies, and implementation trade-offs that separate production-grade grids from naive table implementations.The core challenge: browsers struggle with more than a few thousand DOM nodes. A grid with 100,000 rows and 20 columns would create 2 million cells—rendering all of them guarantees a frozen UI. Every major grid library solves this through virtualization, but their approaches differ significantly in complexity, flexibility, and performance characteristics.

  • Design a File Uploader

    System Design / Frontend System Design 20 min read

    Building robust file upload requires handling browser constraints, network failures, and user experience across a wide spectrum of file sizes and device capabilities. A naive approach—form submission or single XHR (XMLHttpRequest)—fails at scale: large files exhaust memory, network interruptions lose progress, and users see no feedback. Production uploaders solve this through chunked uploads, resumable protocols, and careful memory management.