Uncompressed text responses (HTML, CSS, JS, SVG, JSON) and the Core Web Vitals
42.8% of audited sites (90,283) ship at least one uncompressed text resource (85% good LCP, 1.4s median), trailing sites that compress every text response (57.2%, 87% good LCP, 1.3s median).
57.2% of sites use full text compression text compression coverage, and 87% of those sites have a good LCP, against 86% of all sites.
LCP pass rate
Sites with full text compression text compression coverage have a good LCP most often: 87%, against 86% of all sites. Sites with uncompressed text responses text compression have it least often, at 85%.
Text compression coverage usage
Full text compression is the most used: 57.2% of sites.
How leaking uncompressed text responses affects the four LCP phases
Across the four LCP sub-parts in Chrome's field data, the largest gap between full text compression and uncompressed text responses sits in resource load delay: 237 ms median for full text compression against 315 ms for uncompressed text responses. Overall median field LCP is 1.3s for full text compression (TTFB 601 ms, load delay 237 ms, load duration 112 ms, render delay 187 ms) versus 1.4s for uncompressed text responses.
Understanding uncompressed text responses
Where uncompressed text responses slip through on modern web stacks
Almost no server intentionally disables compression globally. Instead, uncompressed text responses slip through narrow MIME-type allowlists (forgetting image/svg+xml or application/json in nginx or Apache) or come from third-party API and widget endpoints that bypass the primary CDN. Across 120,619 sites (57.2%) that compress every text response, good LCP reaches 87% (1.3s median, 601 ms TTFB), whereas the 90,283 sites (42.8%) shipping at least one uncompressed text payload drop to 85% good LCP (1.4s median, 547 ms TTFB).
Enable Brotli or gzip across every compressible MIME type on both your origin server and CDN edge: text/html, text/css, application/javascript, application/json, image/svg+xml, and font/ttf. Text resources shrink by 70% to 85% when compressed; leaving a render-blocking stylesheet, SVG hero, or hydration JSON payload uncompressed multiplies wire transfer time on mobile networks. Across the dataset, 57.2% of sites compress all text responses (87% good LCP, 1.3s median) while 42.8% ship at least one uncompressed text file (85% good LCP, 1.4s median).
How text compression coverage plays out per platform
What the field data shows when you isolate a single CMS or framework.
WordPress 65,509 sites 33.0% of WordPress sites serve at least one uncompressed text response (71% vs 78% good LCP, 7 percentage points apart).
Across WordPress, 67.0% of sites compress every text resource (78% good LCP, 1.7s median) and 33.0% serve at least one uncompressed HTML, CSS, JS, JSON, or SVG response (71% good LCP, 1.9s median).
Shopify 8,573 stores 68.5% of Shopify stores include at least one uncompressed text response (96% vs 98% good LCP).
Across Shopify storefronts, 31.5% compress every text response (98% good LCP, 1.1s median) and 68.5% include at least one uncompressed text response (96% good LCP, 1.3s median).
React & Next.js 9,570 sites 57.9% of React & Next.js sites ship at least one uncompressed JSON, SVG, or script response.
Across React sites, 42.1% compress every text asset (80% good LCP, 1.5s median) and 57.9% include at least one uncompressed text response (78% good LCP, 1.6s median).
By Arjen Karel · 210,902 crawled sites (69,745 with desktop Chrome field data, October 2026). How we measured.