The State of Web Vitals

HTML document compression on Wix sites

Brotli (br), Gzip, Zstandard (zstd), or uncompressed HTML: how document compression affects Time to First Byte (419 ms on Brotli vs 1327 ms on Gzip) and Largest Contentful Paint.

Field data PhoneDesktopAll Scope All sites October 2026 edition · All devices field outcomes · Wix sites only
Wix Scoped to 5,623 sites out of 203,892 analyzed (cms) Compare with all sites →

2.1% of Wix sites have no HTML compression. Of the 97.9% that do, 99% use Brotli, and 94% of those sites have a good LCP, against 94% of all Wix sites.

The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 5,333 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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LCP pass rate

Sites with Brotli HTML compression have a good LCP most often: 94%, against 94% of all Wix sites.

SitesGood, needs improvement, poor LCPMedian
All Wix sites5,33394%1.2s
Brotli (br) 97.2%5,18294%1.2s
Zstandard (zstd) 0.6%3394%1.3s
Uncompressed (none) 2.1%11494%1.2s
Gzip 0.1%450%1.4s
GoodNeeds improvementPoorSites: with Chrome field data
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 5,333 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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HTML compression usage

97.9% of Wix sites use HTML compression, and 99% of those use Brotli.

All Wix sites 5,621 sites
HTML compression 97.9%
Sites with HTML compression 5,504 sites
Brotli (br) 99.3%
Brotli (br) 99.3% Zstandard (zstd) 0.7% Gzip 0.1%
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 5,333 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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Where HTML compression shows up in the four LCP phases

Across the four LCP sub-parts in Chrome's field data, the largest gap between Brotli and no sits in resource load delay: 456 ms median for Brotli against 418 ms for no. Overall median field LCP is 1.2s for Brotli (TTFB 419 ms, load delay 456 ms, load duration 137 ms, render delay 151 ms) versus 1.1s for no.

Median LCP phase breakdown (Chrome field p75) Load delay Median LCP
All Wix sites 3,945419 ms455 ms455 mslab 455 ms1.2s
Uncompressed (none) 80414 ms418 ms418 mslab 418 ms1.1s
Brotli (br) 3,837419 ms456 ms456 mslab 456 ms1.2s
TTFB Resource load delay Resource load time Element render delay
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 5,333 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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HTML compression per framework

React sets the HTML compression to Brotli on 97% of its sites, and 94% of React sites have a good LCP, against 94% of all sites.

FrameworkHTML compression on its sitesGood LCP
All Wix sites 5,621 sitesBrotli (br) 97%94%
React 5,620 sitesBrotli (br) 97%94%
Brotli (br) Uncompressed (none) Zstandard (zstd) Gzip
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 5,333 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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HTML compression or the framework

Does the framework explain the HTML compression difference?

Almost every site with Brotli HTML compression is a React site, and almost every React site has Brotli HTML compression, so the data can't tell Brotli HTML compression and React apart.

Why Brotli HTML compression speeds up resource discovery

Brotli uses a built-in dictionary of common HTML, CSS, and JavaScript tokens, shrinking HTML documents 15 to 20 percent more than Gzip at comparable CPU cost. Because the browser's preload scanner parses the HTML stream chunk by chunk as it arrives, a smaller compressed document delivers the <head> and hero <img> markup in fewer TCP or QUIC packets. Sites serving Brotli HTML record a 419 ms median TTFB and 1.2s median LCP, compared with 1327 ms TTFB and 1.4s LCP on Gzip.

The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 5,333 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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Understanding HTML document compression

Enable Brotli (br) compression on your HTML responses and keep Gzip as a fallback. Across all audited sites, 97.2% serve Brotli-compressed HTML and reach 94% good LCP (1.2s median), beating Gzip (0.1% of sites, 50% good LCP) and uncompressed HTML (2.1% of sites, 94% good LCP). For dynamic HTML generated on the fly, Brotli quality level 4 or 5 compresses faster AND smaller than Gzip level 6 without adding server CPU delay.

Go fix it Configure Cloudflare for passing the Core Web Vitals → Compression mix →
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 5,333 with all devices field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
Related signals HTTP protocol mix → Connection hints → Cache strategy mix → Uncompressed text responses → By Arjen Karel · 5,621 crawled Wix sites (5,333 with all devices Chrome field data, October 2026) · How we measured