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Web Performance Checklist - Online Quick Audit

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Web Performance Checklist

35 checks
Page Scan Results
Network & Server
HTTPS Enabled -
TTFB (Time to First Byte) -
DNS Lookup Time -
TCP Connection Time -
Page Metrics
DOM Nodes Count -
DOMContentLoaded -
Full Page Load -
Resources Loaded -
These metrics reflect the current page. For a full audit of your own site, embed this tool on your domain.
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Critical Items Done
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Server & Network Critical
Modern protocols offer multiplexing and header compression for faster delivery.
Compress text-based assets to reduce transfer size by 60-80%.
Use Cache-Control, ETag, and max-age for static resources.
Distribute content globally to reduce latency for all users.
Minimize third-party domains to speed up initial connection.
Time to First Byte should be fast; optimize server response time.
Ensure secure connections; HTTP/2 requires HTTPS in all major browsers.
Asset Optimization Critical
Remove whitespace, comments, and unnecessary characters from code.
Use tools like Squoosh or TinyPNG; aim for WebP or AVIF format.
Use loading="lazy" attribute or Intersection Observer for off-screen content.
Tree-shake and eliminate dead code; use PurgeCSS or similar tools.
Modern formats provide 30-50% better compression than JPEG/PNG.
Split JS bundles to load only what's needed for each page/route.
Excessive DOM size harms performance; aim for a lean structure.
Rendering Performance Important
Defer or async non-critical CSS/JS; inline critical CSS in <head>.
Prevent invisible text during font loading; improve perceived speed.
Reserve space for images, ads, and embeds to prevent content jumps.
Prioritize visible content; minimize the number of critical resources.
Use defer or async attributes; load scripts after initial render.
Improve scroll performance by marking touch/wheel listeners as passive.
Break up long JS tasks to keep the main thread responsive to user input.
User Experience Important
First Contentful Paint should happen quickly for a good first impression.
Largest Contentful Paint is a Core Web Vital; target < 2.5s for good rating.
First Input Delay measures interactivity; keep the main thread free.
Buttons, links, and form elements should respond instantly to interaction.
Show placeholder UI while content loads to reduce perceived wait time.
Use transform and opacity for animations; avoid layout-triggering properties.
Responsive design with touch-friendly targets and fast mobile load times.
SEO & Monitoring Recommended
Title, description, and Open Graph tags help search engines and social sharing.
Rich snippets improve CTR; implement JSON-LD structured data.
Real User Monitoring captures actual user experience in the field.
Use Lighthouse CI or similar to catch regressions before deployment.
Run PageSpeed Insights or Lighthouse audits monthly to track progress.
Google Search Console provides field data for LCP, FID, and CLS.
Smaller pages load faster on slow connections; aim for lean pages.

Frequently Asked Questions

A Web Performance Checklist is a structured list of best practices and action items designed to help developers and site owners optimize their website's speed, responsiveness, and overall user experience. It covers areas like server configuration, asset optimization, rendering performance, and Core Web Vitals compliance.

Website performance directly impacts user experience, conversion rates, and SEO rankings. Studies show that a 1-second delay in page load can reduce conversions by 7%. Google uses Core Web Vitals as ranking signals, making performance a critical factor for organic search visibility. Fast sites also have lower bounce rates and higher user engagement.

Core Web Vitals are three key performance metrics defined by Google: LCP (Largest Contentful Paint) measures loading performance and should be under 2.5 seconds; FID (First Input Delay) or INP (Interaction to Next Paint) measures interactivity and should be under 100ms; CLS (Cumulative Layout Shift) measures visual stability and should be under 0.1. These metrics affect your site's search ranking.

You can use tools like Google PageSpeed Insights, Lighthouse (built into Chrome DevTools), WebPageTest, and Chrome User Experience Report (CrUX). For continuous monitoring, implement Real User Monitoring (RUM) solutions and set up Lighthouse CI in your deployment pipeline to catch regressions early.

Google recommends that pages should load within 2-3 seconds for optimal user experience. For e-commerce sites, a load time under 2 seconds is strongly recommended, as 53% of mobile users abandon sites that take longer than 3 seconds to load. Aim for FCP under 1.8s and LCP under 2.5s for good Core Web Vitals scores.

Images often account for 50-70% of a page's total weight. Optimizing images—by compressing them, using modern formats like WebP/AVIF, implementing responsive images with srcset, and lazy loading off-screen images—can dramatically reduce page size and improve LCP scores. Proper image optimization is one of the highest-impact performance improvements you can make.

TTFB (Time to First Byte) measures the time from the browser's request to receiving the first byte of the response. A good TTFB is under 800ms, with excellent scores under 200ms. High TTFB indicates server-side issues like slow database queries, insufficient server resources, or lack of caching. It directly impacts all subsequent loading metrics including LCP.

To reduce render-blocking resources: inline critical CSS directly in the <head>, defer non-critical JavaScript using async or defer attributes, split CSS into critical and non-critical files, and use media attributes to conditionally load stylesheets. Also consider preloading key resources with <link rel="preload"> to prioritize their fetching.

Lazy loading defers the loading of non-critical resources (like images, videos, and iframes) until they are about to enter the viewport. This reduces initial page load time, saves bandwidth, and improves LCP and FCP. Modern browsers support native lazy loading via the loading="lazy" attribute on <img> and <iframe> elements. For advanced use cases, the Intersection Observer API provides more control.

Ideally, you should run performance audits with every significant code change by integrating Lighthouse CI into your deployment pipeline. At minimum, conduct a full manual audit monthly using tools like PageSpeed Insights and WebPageTest. Also monitor Core Web Vitals continuously through Google Search Console and Real User Monitoring (RUM) tools to catch real-world performance issues.
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