On 14 April 2019, we announced the introduction of HTTP/3 support with QUIC in our hosting plans, including the Onyx and Cóndor plans offered at the time. It was an early step in the evolution of the protocols connecting your website to its visitors.
HTTP/3 retains HTTP’s purpose: requesting and delivering pages, images and other resources. What changes is how those data are transported, with improvements that are particularly useful when a connection has delays or loses packets.
How HTTP/3 works
HTTP/3 uses QUIC, a transport protocol over UDP, instead of the TCP connection used by HTTP/2. QUIC combines connection establishment with encryption through TLS 1.3.
It also manages multiple data streams within a connection. If a packet belonging to one stream is lost, the others do not need to wait for its recovery because of the same transport-level blocking that can affect HTTP/2.
HTTP/3 and QUIC are related technologies with different roles: HTTP/3 organises web exchanges, while QUIC transports their data. The Cloudflare technical explanation explores these concepts.
What improves for your visitors?
- Fewer exchanges to establish a connection. Combining transport and encryption helps reduce the initial wait.
- Better handling of packet loss. Independent streams prevent one loss from stopping every transfer on a connection.
- Adaptation to network changes. QUIC can keep a connection alive when changing networks, where conditions and the implementation allow it.
- Integrated encryption. Application communications travel over a protected connection.
For a store or a site with mobile visitors, these improvements help deliver content with fewer interruptions. The actual difference depends on the network, browser and website; it is not a fixed percentage speed increase.
What you need to use it
The browser and server must support HTTP/3, the site must use HTTPS and the network must allow the necessary traffic. Protocol negotiation happens automatically: you do not need to rewrite WordPress or change your pages’ code.
When HTTP/3 cannot be used, a compatible browser can connect through HTTP/2 or HTTP/1.1. If your domain uses a CDN or proxy, the protocol visitors see also depends on that intermediary.
An improvement managed through your hosting
We manage server configuration as part of our web hosting infrastructure. HTTP/3 complements improvements such as HTTP/2, HTTPS and application optimisation.
To check which protocol your domain uses or review a Cloudflare configuration, write to us. We can help distinguish the visitor’s connection from the connection to the origin server.