Lighthouse: Use HTTP/2 for all resources
HTTP/2 overcomes many of the limitations seen in HTTP/1.1 including, higher connection limit to handle more parallel requests, and lower protocol overhead.
This can drastically speed up page loads, make web applications faster, and make the application itself robust.
How does your site score on this audit?
How does using HTTP/2 for all of the page resources affect page performance?
Serving resources using HTTP/1.1 can affect your page load due to a lower connection limit, which causes network congestion. This is especially pronounced in pages with large number of requests.
In general, HTTP/1.1 may also suffer from poor performance due to significant overheads associated with your page requests.
Serving requests over HTTP/2 may improve page load times by up to 50% compared to HTTP/1.1 pages.
HTTP/2 overcomes the HTTP/1.1 protocol's limitations by enabling full request and resource multiplexing. This means that more requests can be made on a single connection compared to HTTP/1.1.
HTTP/2 also minimizes protocol overhead by compressing the header fields, and further supports request prioritization, among other improvements.
In summary, HTTP/2 allows more efficient handling of pages with a large number of requests, compared to HTTP/1.1
How does GTmetrix trigger this audit?
GTmetrix flags the resources (host only, not third-party) that aren't served using HTTP/2. Clicking the audit reveals the non-HTTP/2 resources.
How to fix this audit?
To avoid triggering this audit, serve your resources over HTTP/2.
Check with your hosting provider if HTTP/2 is enabled on your server.