At a glance the headline numbers for Uncompressed text responses
Whether any text response shipped uncompressed.
44.7% of sites ship at least one uncompressed text response.
Uncompressed text responses sites that have it vs sites that don't
44.7% of sites serve uncompressed text resources (42,460 of 94,910). With serve: CLS 0.00, 86.6% pass. Without: CLS 0.00, 90.8% pass. computed
Why this matters for the Core Web Vitals, and where to start fixing it
One uncompressed text response is usually a configuration gap, not a decision. A server that compresses HTML but forgets SVG. An API endpoint that bypasses the CDN. The cost lands wherever the file sits: an uncompressed stylesheet delays rendering and the LCP, an uncompressed JSON response delays whatever waited for it.
Compression is a server or CDN switch. Find the response, find why it bypassed the rule, turn it on. The compression mix page shows how the rest of the fleet does.
How does missing compression affect the Core Web Vitals?
Having it makes no measurable difference to the LCP: 81% pass with it, 83% without.
Chrome field data from 94,910 sites, representing millions of real page loads. How we measured.