--- title: Find Hidden Render-Blocking Requests with the Website... description: Chrome's render-blocking label only flags synchronous parser-blocking resources in the head, missing many requests that actually delay FCP and LCP — like... canonical: https://daily.dev/posts/find-hidden-render-blocking-requests-with-the-website-bottleneck-finder-ccb9ti69s twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Find Hidden Render-Blocking Requests with the Website Bottleneck Finder | daily.dev og:description: Chrome's render-blocking label only flags synchronous parser-blocking resources in the head, missing many requests that actually delay FCP and LCP — like... og:url: https://daily.dev/posts/find-hidden-render-blocking-requests-with-the-website-bottleneck-finder-ccb9ti69s og:image: https://api.daily.dev/og/posts/CCB9ti69S.png og:image:alt: Find Hidden Render-Blocking Requests with the Website Bottleneck Finder og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Find Hidden Render-Blocking Requests with the Website Bottleneck Finder **[DebugBear](https://daily.dev/sources/debugbear)** · 6 min read · 0 upvotes · 0 comments ## Summary Chrome's render-blocking label only flags synchronous parser-blocking resources in the head, missing many requests that actually delay FCP and LCP — like deferred scripts that gate SPA data fetches, code-split chunks, and the LCP image itself. DebugBear's Website Bottleneck Finder addresses this by replaying page loads with cached responses, delaying one resource at a time by 2 seconds, and flagging any resource that pushes FCP/LCP back by half the delay or more. A real-world example on virginatlantic.com shows how the tool identified which of 23 deferred JS scripts was impacting LCP, and preloading it yielded a 25%+ LCP improvement. The tool is free to use and can be paired with full Lighthouse analysis or continuous monitoring. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Similar posts on daily.dev - [The Anatomy of LCP - A Deep Dive into Sub-Parts](https://daily.dev/posts/the-anatomy-of-lcp---a-deep-dive-into-sub-parts-8oihjobmo) · Web Performance Calendar · 0 upvotes · 0 comments - [Insights from 100 site speed reviews in 2025](https://daily.dev/posts/insights-from-100-site-speed-reviews-in-2025-yh4tk3cne) · Web Performance Calendar · 0 upvotes · 0 comments - [Web Performance 2025: The Shift from Optimization to Prediction](https://daily.dev/posts/web-performance-2025-the-shift-from-optimization-to-prediction-emdlyovyv) · Web Performance Calendar · 0 upvotes · 0 comments --- Tags: [#webdev](https://daily.dev/tags/webdev) [View this post on daily.dev](https://daily.dev/posts/find-hidden-render-blocking-requests-with-the-website-bottleneck-finder-ccb9ti69s) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Find Hidden Render-Blocking Requests with the Website Bottleneck Finder","url":"https://daily.dev/posts/find-hidden-render-blocking-requests-with-the-website-bottleneck-finder-ccb9ti69s","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/find-hidden-render-blocking-requests-with-the-website-bottleneck-finder-ccb9ti69s"},"datePublished":"2026-07-29T12:35:49.020Z","dateModified":"2026-07-29T12:36:12.085Z","description":"Chrome's render-blocking label only flags synchronous parser-blocking resources in the head, missing many requests that actually delay FCP and LCP — like...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/65bd33270a5233e1e363c9e3ac7018cc?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/65bd33270a5233e1e363c9e3ac7018cc?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"DebugBear","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"DebugBear","logo":"https://media.daily.dev/image/upload/s--LFz7F9sP--/f_auto,q_auto/v1780213580/logos/debugbear?_a=BAMAMiWQ0","url":"https://daily.dev/sources/debugbear"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/find-hidden-render-blocking-requests-with-the-website-bottleneck-finder-ccb9ti69s","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":0},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"webdev","timeRequired":"PT6M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"DebugBear","item":"https://daily.dev/sources/debugbear"},{"@type":"ListItem","position":3,"name":"Find Hidden Render-Blocking Requests with the Website Bottleneck Finder"}]} ```