The State of Web Vitals

HTTP cache TTL tiers on Wix sites

Unspecified cache headers (100.0%), long TTLs (99.9%), medium TTLs (99.9%), no-store (99.9%), short TTLs (47.9%), no-cache (99.9%), and Cache-Control: immutable (99.9%).

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

100.0% of Wix sites use unspecified cache HTTP cache TTL tiers, 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 · 3,077 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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LCP pass rate

Sites with unspecified cache HTTP cache TTL tiers have a good LCP most often: 94%, against 94% of all Wix sites. Sites with short-TTL cache tiers have it least often, at 92%.

SitesGood, needs improvement, poor LCPMedian
All Wix sites3,07794%1.1s
Unspecified cache lifetime 100.0%3,07794%1.1s
Long TTL (> 30 days) 99.9%3,07694%1.1s
Medium TTL (1 - 30 days) 99.9%3,07694%1.1s
Cache-Control: immutable 99.9%3,07694%1.1s
Cache-Control: no-store 99.9%3,07694%1.1s
Cache-Control: no-cache 99.9%3,07594%1.1s
Short TTL (< 1 day) 47.9%1,40292%1.2s
GoodNeeds improvementPoorSites: with Chrome field data
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 3,077 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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HTTP cache TTL tiers usage

Unspecified cache is the most used: 100.0% of Wix sites.

Sites using each option (sites can use more than one) 5,621 sites
Unspecified cache lifetime 100.0% Long TTL (> 30 days) 99.9% Medium TTL (1 - 30 days) 99.9% Cache-Control: immutable 99.9% Cache-Control: no-store 99.9% Cache-Control: no-cache 99.9%
Unspecified cache lifetime 100.0% Long TTL (> 30 days) 99.9% Medium TTL (1 - 30 days) 99.9% Cache-Control: immutable 99.9% Cache-Control: no-store 99.9% Cache-Control: no-cache 99.9% Short TTL (< 1 day) 47.9%
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 3,077 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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How HTTP cache TTL tiers affect the four LCP phases

Across the four LCP sub-parts in Chrome's field data, the largest gap between unspecified cache and short-TTL sits in time to first byte (TTFB): 404 ms median for unspecified cache against 432 ms for short-TTL. Overall median field LCP is 1.1s for unspecified cache (TTFB 404 ms, load delay 446 ms, load duration 110 ms, render delay 150 ms) versus 1.2s for short-TTL.

Median LCP phase breakdown (Chrome field p75) Load delay Median LCP
All Wix sites 2,353404 ms446 ms150 ms446 mslab 453 ms1.1s
Long TTL (> 30 days) 2,353404 ms446 ms150 ms446 mslab 453 ms1.1s
Unspecified cache lifetime 2,353404 ms446 ms150 ms446 mslab 453 ms1.1s
Cache-Control: no-store 2,353404 ms446 ms150 ms446 mslab 453 ms1.1s
Cache-Control: no-cache 2,353404 ms446 ms150 ms446 mslab 453 ms1.1s
Medium TTL (1 - 30 days) 2,353404 ms446 ms150 ms446 mslab 453 ms1.1s
Cache-Control: immutable 2,353404 ms446 ms150 ms446 mslab 453 ms1.1s
Short TTL (< 1 day) 1,038432 ms461 ms151 ms461 mslab 473 ms1.2s
TTFB Resource load delay Resource load time Element render delay
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 3,077 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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HTTP cache TTL tiers per framework

React sets the HTTP cache TTL tiers to unspecified cache on 100% of its sites, and 94% of React sites have a good LCP, against 94% of all sites.

FrameworkHTTP cache TTL tiers on its sitesGood LCP
All Wix sites 5,621 sitesUnspecified cache lifetime 100%Long TTL (> 30 days) 100%Medium TTL (1 - 30 days) 100%Cache-Control: immutable 100%Cache-Control: no-store 100%Cache-Control: no-cache 100%Short TTL (< 1 day) 48%94%
React 5,620 sitesCache-Control: immutable 100%Medium TTL (1 - 30 days) 100%Unspecified cache lifetime 100%Long TTL (> 30 days) 100%Cache-Control: no-store 100%Cache-Control: no-cache 100%Short TTL (< 1 day) 48%94%
Unspecified cache lifetime Long TTL (> 30 days) Medium TTL (1 - 30 days) Cache-Control: immutable Cache-Control: no-store Cache-Control: no-cache Short TTL (< 1 day)
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 3,077 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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HTTP cache TTL tiers or the framework

Does the framework explain the HTTP cache TTL tiers difference?

Almost every site with unspecified cache HTTP cache TTL tiers is a React site, and almost every React site has unspecified cache HTTP cache TTL tiers, so the data can't tell unspecified cache HTTP cache TTL tiers and React apart.

How Cache-Control: immutable and long TTLs accelerate repeat views

Field Core Web Vitals combine first visits and repeat navigations from Chrome users. Sites that serve content-hashed static bundles with Cache-Control: immutable (99.9% of sites) achieve 94% good field LCP (1.1s median LCP), outperforming sites limited to short TTLs (47.9%, 92% good LCP) or no-store responses (99.9%, 94% good LCP).

The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 3,077 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
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Understanding HTTP cache TTL tiers

Fingerprint static CSS, JavaScript, and font filenames and serve them with Cache-Control: public, max-age=31536000, immutable. While 99.9% of sites use long cache TTLs, only 99.9% include the immutable directive (94% good LCP), which prevents unnecessary 304 revalidation round-trips when users reload or navigate across pages.

Go fix it TTFB: cache duration → Configure Cloudflare for passing the Core Web Vitals →
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 3,077 with phone field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
Related signals Cacheable responses → HTTP protocol mix → HTML size (kB) → Last-Modified present → By Arjen Karel · 5,621 crawled Wix sites (3,077 with phone Chrome field data, October 2026) · How we measured