Web Architecture & System Design

• Critical Rendering Path

  12 min read • Published on October 1, 2023 • Last Updated On July 14, 2025

  Learn how browsers convert HTML, CSS, and JavaScript into pixels, understanding DOM construction, CSSOM building, layout calculations, and paint operations for optimal web performance.TLDRCritical Rendering Path (CRP) is the browser’s six-stage process of converting HTML, CSS, and JavaScript into visual pixels, with each stage potentially creating performance bottlenecks that impact user experience metrics.Six-Stage Rendering PipelineDOM Construction: HTML parsing into tree structure with incremental parsing for early resource discoveryCSSOM Construction: CSS parsing into style tree with cascading and render-blocking behaviorRender Tree: Combination of DOM and CSSOM with only visible elements includedLayout (Reflow): Calculating exact size and position of each element (expensive operation)Paint (Rasterization): Drawing pixels for each element onto layers in memoryCompositing: Assembling layers into final image using separate compositor threadBlocking BehaviorsCSS Render Blocking: CSS blocks rendering to prevent FOUC and ensure correct cascadingJavaScript Parser Blocking: Scripts block HTML parsing when accessing DOM or stylesJavaScript CSS Blocking: Scripts accessing computed styles must wait for CSS to loadLayout Thrashing: Repeated layout calculations caused by JavaScript reading/writing layout propertiesJavaScript Loading StrategiesDefault (Parser-blocking): Blocks HTML parsing until script downloads and executesAsync: Non-blocking, executes immediately when downloaded (order not preserved)Defer: Non-blocking, executes after DOM parsing (order preserved)Module: Deferred by default, supports imports/exports and top-level awaitPerformance OptimizationPreload Scanner: Parallel resource discovery for declarative resources in HTMLCompositor Thread: GPU-accelerated animations using transform/opacity propertiesLayer Management: Separate layers for transform, opacity, will-change, 3D transformsNetwork Protocols: HTTP/2 multiplexing and HTTP/3 QUIC for faster resource deliveryCommon Performance IssuesLayout Thrashing: JavaScript forcing repeated layout calculations in loopsStyle Recalculation: Large CSS selectors and high-level style changesRender-blocking Resources: CSS and JavaScript delaying First Contentful PaintMain Thread Blocking: Long JavaScript tasks preventing layout and paint operationsBrowser Threading ModelMain Thread: Handles parsing, styling, layout, painting, and JavaScript executionCompositor Thread: Handles layer assembly, scrolling, and GPU-accelerated animationsThread Separation: Enables smooth scrolling and animations even with main thread workDiagnostic ToolsChrome DevTools Performance Panel: Visualizes main thread work and bottlenecksNetwork Panel Waterfall: Shows resource dependencies and blockingLighthouse: Identifies render-blocking resources and critical request chainsLayers Panel: Diagnoses compositor layer issues and explosionsBest PracticesDeclarative Resources: Use <img> tags and SSR/SSG for critical contentCSS Optimization: Minimize render-blocking CSS with media attributesJavaScript Loading: Use defer/async appropriately for script dependenciesLayout Optimization: Avoid layout thrashing with batched DOM operationsAnimation Performance: Use transform/opacity for GPU-accelerated animations

• High-Performance Static Site Generation on AWS

  28 min read • Published on October 15, 2023 • Last Updated On July 17, 2025

  Master production-grade SSG architecture with deployment strategies, performance optimization techniques, and advanced AWS patterns for building fast, scalable static sites.TLDRStatic Site Generation (SSG) is a build-time rendering approach that pre-generates HTML, CSS, and JavaScript files for exceptional performance, security, and scalability when deployed on AWS with CloudFront CDN.Core SSG PrinciplesBuild-Time Rendering: All pages generated at build time, not request timeStatic Assets: Pure HTML, CSS, JS files served from CDN edge locationsContent Sources: Markdown files, headless CMS APIs, or structured dataTemplates/Components: React, Vue, or templating languages for page generationGlobal CDN: Deployed to edge locations worldwide for instant deliveryRendering Spectrum ComparisonSSG: Fastest TTFB, excellent SEO, stale data, lowest infrastructure complexitySSR: Slower TTFB, excellent SEO, real-time data, highest infrastructure complexityCSR: Slowest TTFB, poor SEO, real-time data, low infrastructure complexityHybrid: Per-page rendering decisions for optimal performance and functionalityAdvanced AWS ArchitectureAtomic Deployments: Versioned directories in S3 (e.g., /build_001/, /build_002/)Instant Rollbacks: CloudFront origin path updates for zero-downtime rollbacksLambda@Edge: Dynamic routing, redirects, and content negotiation at the edgeBlue-Green Deployments: Parallel environments with traffic switching via cookiesCanary Releases: Gradual traffic shifting for risk mitigationPerformance OptimizationPre-Compression: Brotli (Q11) and Gzip (-9) compression during build processContent Negotiation: Lambda@Edge function serving optimal compression formatCLS Prevention: Image dimensions, font optimization, responsive component renderingAsset Delivery: Organized S3 structure with proper metadata and cache headersEdge Caching: CloudFront cache policies with optimal TTL valuesDeployment StrategiesVersioned Deployments: Each build in unique S3 directory with build version headersRollback Mechanisms: Instant rollbacks via CloudFront origin path updatesCache Invalidation: Strategic cache purging for new deploymentsZero-Downtime: Atomic deployments with instant traffic switchingA/B Testing: Lambda@Edge routing based on user cookies or IP hashingAdvanced PatternsDual Build Strategy: Separate mobile/desktop builds for optimal CLS preventionEdge Redirects: High-performance redirects handled at CloudFront edgePre-Compressed Assets: Build-time compression with content negotiationResponsive Rendering: Device-specific builds with user agent detectionGradual Rollouts: Canary releases with percentage-based traffic routingPerformance BenefitsTTFB: <50ms (vs 200-500ms for SSR)Compression Ratios: 85-90% bandwidth savings with pre-compressionGlobal Delivery: Edge locations worldwide for instant accessScalability: CDN handles unlimited traffic without server scalingSecurity: Reduced attack surface with no server-side code executionBest PracticesBuild Optimization: Parallel builds, incremental generation, asset optimizationCache Strategy: Aggressive caching with proper cache invalidationMonitoring: Real-time metrics, performance monitoring, error trackingSEO Optimization: Static sitemaps, meta tags, structured dataSecurity: HTTPS enforcement, security headers, CSP policies

• Microfrontends Architecture

  17 min read • Published on November 1, 2023 • Last Updated On January 27, 2024

  Learn how to scale frontend development with microfrontends, enabling team autonomy, independent deployments, and domain-driven boundaries for large-scale applications.TLDRMicrofrontends break large frontend applications into smaller, independent pieces that can be developed, deployed, and scaled separately.Key BenefitsTeam Autonomy: Each team owns their microfrontend end-to-endTechnology Freedom: Teams can choose different frameworks (React, Vue, Angular, Svelte)Independent Deployments: Deploy without coordinating with other teamsDomain-Driven Design: Organized around business domains, not technical layersComposition StrategiesClient-Side: Browser assembly using Module Federation, Web Components, iframesServer-Side: Server assembly using SSR frameworks, Server-Side IncludesEdge-Side: CDN assembly using Cloudflare Workers, ESI, Lambda@EdgeIntegration TechniquesIframes: Maximum isolation, complex communication via postMessageWeb Components: Framework-agnostic, encapsulated UI widgetsModule Federation: Dynamic code sharing, dependency optimizationCustom Events: Simple publish-subscribe communicationDeployment & State ManagementIndependent CI/CD pipelines for each microfrontendLocal state first - each microfrontend manages its own stateURL-based state for sharing ephemeral dataCustom events for cross-microfrontend communicationWhen to ChooseClient-Side: High interactivity, complex state sharing, SPA requirementsEdge-Side: Global performance, low latency, high availability needsServer-Side: SEO-critical, initial load performance priorityIframes: Legacy integration, security sandboxing requirementsChallengesCross-cutting concerns: State management, routing, user experiencePerformance overhead: Multiple JavaScript bundles, network requestsComplexity: Requires mature CI/CD, automation, and toolingTeam coordination: Shared dependencies, versioning, integration testing