TL;DR HTTP/2
HTTP/2 is the second major version of the Hypertext Transfer Protocol, the foundation of data communication on the web. The original HTTP/1.1 protocol loads resources one at a time over a single connection, which creates a queue that slows page loads when a browser needs to fetch many files simultaneously. HTTP/2 solves this by introducing multiplexing, which allows multiple requests and responses to travel over a single connection at the same time. It also introduces header compression and server push, both of which reduce the overhead of each request. The practical result is noticeably faster page loads, particularly on pages with many assets like images, scripts, and stylesheets. CloudSonic enables HTTP/2 on every server by default, so your site benefits automatically. Combined with Brotli compression and a good CDN, HTTP/2 makes a meaningful difference to your Core Web Vitals scores.
How HTTP/2 Works
HTTP/2 addresses the fundamental inefficiency of HTTP/1.1 through several key changes to how data is transferred. The most significant is multiplexing, which allows multiple requests and responses to travel over a single connection simultaneously rather than queuing behind each other. In HTTP/1.1 a browser opens multiple parallel connections to work around this limitation, typically six per domain, but each connection still has its own overhead. HTTP/2 replaces this with a single connection that handles many streams in parallel. It also compresses HTTP headers, which in HTTP/1.1 are sent in plain text with every request and can add significant overhead when cookies and other headers are large. HTTP/2 uses a compression format called HPACK that dramatically reduces header size. Server push allows the server to proactively send resources the browser will need before it asks for them, reducing round trips for critical assets like CSS and fonts.
Why HTTP/2 Matters for Your Website
The practical impact of HTTP/2 is most visible on pages with many assets. A typical WordPress page might load a theme stylesheet, several plugin stylesheets, a main JavaScript file, several plugin scripts, a web font, and multiple images. In HTTP/1.1 these resources are fetched through multiple parallel connections with artificial limits on how many can be open simultaneously. HTTP/2 removes these limits and allows all resources to be requested and received over a single connection in parallel. The result is that pages with many assets load noticeably faster without any changes to the page itself. HTTP/2 also reduces connection overhead because establishing and maintaining multiple connections each with their own TLS handshake is replaced by a single connection. For visitors on high latency connections, such as mobile users or international visitors, this reduction in round trips makes a significant difference to perceived page speed and Core Web Vitals scores.
