The State of Web Vitals

HTTP protocol

The HTTP protocol of the HTML document response.

Field data PhoneDesktopAll Scope All sites Q1 2026 edition · Phone field outcomes
Metric LCP INP CLS
1

At a glance the headline numbers for HTTP protocol

The HTTP protocol of the HTML document response.

3
Categories
94,906 sites
63.1%
Top share
h2
96ms
Top INP
Median for h2

23.9% of HTML documents arrive over HTTP/3.

The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
2

HTTP protocol who uses what, and how fast each group loads

Median INP
0
100ms
200ms
300ms
400ms
500ms
h296ms63% of sites
http/1.1102ms13% of sites
h3103ms24% of sites
VariantShare of sitesMedian
h2 59,859 sites
63%
96ms
http/1.1 12,368 sites
13%
102ms
h3 22,679 sites
24%
103ms

Little daylight between the groups: every variant sits near 96ms median INP. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
3

Passing INP per HTTP protocol which group passes the INP most often

VariantSitesPassing INPINP
H2 63.1% 59,859 93% 96ms
H3 23.9% 22,679 92% 103ms
Http/1.1 13% 12,368 88% 102ms
Good Needs Improvement Poor Sorted best-passing first · median colored by its own rating · pass = good INP (200ms at p75) · one value per site

93% of H2 sites pass INP. Http/1.1 trails 5 points behind. computed

The State of Web Vitals · Q1 2026 · 94,910 sites · phone field datacorewebvitals.io/state-of-cwv
4

Why this matters for the Core Web Vitals, and where to start fixing it

The protocol decides how expensive a connection is. HTTP/3 sets up in fewer round trips and a lost packet no longer stalls everything behind it, which TCP-based protocols suffer from. The document request is where this matters most: it is the first request of the visit and it carries the whole TTFB.

There is a catch on the very first visit. Browsers often discover HTTP/3 support through a header on a previous response (Alt-Svc), so the first document fetch can still pay the older protocol's price. DNS HTTPS records fix that discovery, and your CDN controls whether they exist.

How does this affect the Core Web Vitals?

HTTP protocol correlates with the LCP. With H3, 86% of sites pass the LCP. With H2, 80% do.

Go fix it TTFB: connection duration → Configure Cloudflare for passing the Core Web Vitals →
Related signals Uncompressed text responses → HTML size (kB) → Connection hints → ETag present → Chrome field data from 94,910 sites, representing millions of real page loads · How we measured