The State of Web Vitals

HTTP Last-Modified headers on Wix sites

Whether responses carry Last-Modified validators.

Field data PhoneDesktopAll Scope All sites October 2026 edition · Desktop 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 Last-Modified headers Last-Modified cache validation, and 92% of those sites have a good LCP, against 92% of all Wix sites.

The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 728 with desktop field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
1

LCP pass rate

Sites with Last-Modified headers Last-Modified cache validation have a good LCP most often: 92%, against 92% of all Wix sites.

SitesGood, needs improvement, poor LCPMedian
All Wix sites72892%1.2s
Last-Modified present 100.0%72892%1.2s
GoodNeeds improvementPoorSites: with Chrome field data
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 728 with desktop field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
2

Last-Modified cache validation usage

Last-Modified headers is the most used: 100.0% of Wix sites.

Last-Modified present 100.0%
Last-Modified present 100.0%
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 728 with desktop field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
3

LCP phase breakdown for sites with and without Last-Modified headers

Median LCP phase breakdown (Chrome field p75) Load delay Median LCP
All Wix sites 376343 ms478 ms259 ms137 ms478 mslab 462 ms1.2s
Last-Modified present 376343 ms478 ms259 ms137 ms478 mslab 462 ms1.2s
TTFB Resource load delay Resource load time Element render delay
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 728 with desktop field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
4

Last-Modified cache validation per framework

React sets the Last-Modified cache validation to Last-Modified headers on 100% of its sites, and 92% of React sites have a good LCP, against 92% of all sites.

FrameworkLast-Modified cache validation on its sitesGood LCP
All Wix sites 5,621 sitesLast-Modified present 100%92%
React 5,620 sitesLast-Modified present 100%92%
Last-Modified present
The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 728 with desktop field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
5

Last-Modified headers or the framework

Does the framework explain the Last-Modified cache validation difference?

Almost every site with Last-Modified headers Last-Modified cache validation is a React site, and almost every React site has Last-Modified headers Last-Modified cache validation, so the data can't tell Last-Modified headers Last-Modified cache validation and React apart.

The State of Web Vitals · October 2026 · Wix: 5,621 crawled sites · 728 with desktop field dataBy Arjen Karel · corewebvitals.io/state-of-cwv
Related signals HTTP protocol → HTML size (kB) → Connection hints → HTML compression → By Arjen Karel · 5,621 crawled Wix sites (728 with desktop Chrome field data, October 2026) · How we measured