#Web Performance
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k6 Performance Testing Framework
22 min read • Published on • Last Updated OnMaster k6’s Go-based architecture, JavaScript scripting capabilities, and advanced workload modeling for modern DevOps and CI/CD performance testing workflows.TLDRk6 is a modern, developer-centric performance testing framework built on Go’s goroutines and JavaScript scripting, designed for DevOps and CI/CD workflows with exceptional resource efficiency and scalability.Core ArchitectureGo-based Engine: High-performance execution using goroutines (lightweight threads) instead of OS threadsJavaScript Scripting: ES6-compatible scripting with embedded goja runtime (no Node.js dependency)Resource Efficiency: Single binary with minimal memory footprint (256MB vs 760MB for JMeter)Scalability: Single instance can handle 30,000-40,000 concurrent virtual usersPerformance Testing PatternsSmoke Testing: Minimal load (3 VUs) to verify basic functionality and establish baselinesLoad Testing: Average load assessment with ramping stages to measure normal performanceStress Testing: Extreme loads to identify breaking points and system behavior under stressSoak Testing: Extended periods (8+ hours) to detect memory leaks and performance degradationSpike Testing: Sudden traffic bursts to test system resilience and recovery capabilitiesWorkload ModelingClosed Models (VU-based): Fixed number of virtual users, throughput as outputOpen Models (Arrival-rate): Fixed request rate, VUs as outputScenarios API: Multiple workload profiles in single test with parallel/sequential executionExecutors: Constant VUs, ramping VUs, constant arrival rate, ramping arrival rateAdvanced FeaturesMetrics Framework: Built-in HTTP metrics, custom metrics (Counter, Gauge, Rate, Trend)Thresholds: Automated pass/fail analysis with SLOs codified in test scriptsAsynchronous Execution: Per-VU event loops for complex user behavior simulationData-driven Testing: CSV/JSON data loading with SharedArray for realistic scenariosEnvironment Configuration: Environment variables for multi-environment testingCI/CD IntegrationTests as Code: JavaScript scripts version-controlled in Git with peer reviewAutomated Workflows: Seamless integration with GitHub Actions, Jenkins, GitLab CIShift-left Testing: Early performance validation in development pipelineThreshold Validation: Automated performance regression detectionExtensibility (xk6)Custom Extensions: Native Go extensions for new protocols and integrationsPopular Extensions: Kafka, MQTT, PostgreSQL, MySQL, browser testingOutput Extensions: Custom metric streaming to Prometheus, Elasticsearch, AWSBuild System: xk6 tool for compiling custom k6 binaries with extensionsDeveloper ExperienceJavaScript API: Familiar ES6 syntax with built-in modules (k6/http, k6/check)CLI-first Design: Command-line interface optimized for automationReal-time Output: Live metrics and progress during test executionComprehensive Documentation: Extensive guides and examplesBest PracticesIncremental Complexity: Start with smoke tests, gradually increase loadRealistic Scenarios: Model actual user behavior patternsEnvironment Parity: Test against production-like environmentsMonitoring Integration: Real-time metrics with external monitoring toolsPerformance Baselines: Establish and maintain performance thresholdsCompetitive AdvantagesResource Efficiency: 10x better memory usage compared to JMeterDeveloper Productivity: JavaScript scripting with modern toolingCI/CD Native: Designed for automated testing workflowsScalability: Single instance handles enterprise-scale loadsExtensibility: Custom extensions for specialized requirements
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Web Performance Optimization Overview
18 min read • Published on • Last Updated OnAdvanced techniques for optimizing web application performance across infrastructure, frontend, and modern browser capabilities. Covers Islands Architecture, HTTP/3, edge computing, JavaScript optimization, CSS rendering, image formats, font loading, caching strategies, and performance monitoring.
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Infrastructure Optimization for Web Performance
39 min read • Published on • Last Updated OnMaster infrastructure optimization strategies including DNS optimization, HTTP/3 adoption, CDN configuration, caching, and load balancing to build high-performance websites with sub-second response times.
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JavaScript Performance Optimization
15 min read • Published on • Last Updated OnMaster advanced JavaScript optimization techniques including bundle splitting, long task management, React optimization, and Web Workers for building high-performance web applications.
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Font Optimization for Web Performance
25 min read • Published on • Last Updated OnMaster font optimization techniques including WOFF2 compression, subsetting, variable fonts, and strategic loading to reduce payload by 65-90% and achieve optimal Core Web Vitals scores.
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CSS Performance Optimization
5 min read • Published on • Last Updated OnMaster CSS optimization techniques including critical CSS extraction, animation performance, containment properties, and delivery strategies for faster rendering and better user experience.
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Image Optimization for Web Performance
10 min read • Published on • Last Updated OnMaster responsive image techniques, lazy loading, modern formats like WebP and AVIF, and optimization strategies to improve Core Web Vitals and reduce bandwidth usage by up to 70%.
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Web Performance Patterns
15 min read • Published on • Last Updated OnMaster advanced web performance patterns including Islands Architecture, caching strategies, performance monitoring, and CI/CD automation for building high-performance web applications.
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Microfrontends Architecture
17 min read • Published on • Last Updated OnLearn 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
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High-Performance Static Site Generation on AWS
28 min read • Published on • Last Updated OnMaster 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
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Critical Rendering Path
12 min read • Published on • Last Updated OnLearn 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
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Image Formats for Web Performance
5 min read • Published onMaster modern image formats including JPEG, WebP, AVIF, and PNG, understanding compression algorithms, color spaces, HDR support, and optimal deployment strategies.
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Web Accessibility
13 min read • Published onLearn WCAG guidelines, semantic HTML, ARIA attributes, and screen reader optimization to create inclusive websites that work for everyone, including users with disabilities.
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Web Protocol Evolution: HTTP/1.1 to HTTP/3 and TLS Handshake Optimization
25 min read • Published onA comprehensive analysis of web protocol evolution revealing how HTTP/1.1’s application-layer bottlenecks led to HTTP/2’s transport-layer constraints, ultimately driving the adoption of HTTP/3 with QUIC. This exploration examines TLS handshake optimization, protocol negotiation mechanisms, DNS-based discovery, and the sophisticated browser algorithms that determine optimal protocol selection based on network conditions and server capabilities.