HTTP/3 is the newest version of the protocol browsers use to fetch websites. For an online store, it means a shorter wait before the page starts arriving, and a more stable experience on mobile, where the connection fluctuates. It’s no revolution, but it’s a free improvement that most people can turn on without touching the store itself.
What does HTTP/3 change?
HTTP/1.1 and HTTP/2 send data over TCP, a protocol from the 1970s. HTTP/3 uses QUIC instead, a new transport protocol on top of UDP with encryption built right in. The content itself, the pages, images and code, is the same. What changes is how it gets there.
The first difference is felt before the page even starts arriving. With TCP and TLS, the browser and server first have to set up the connection and then the encryption, each in its own round trip. QUIC handles both in one, and on repeat visits the browser can send its request right away. On a mobile connection, where each round trip can take many milliseconds, that’s noticeable.
The second difference is about lost packets. HTTP/2 fetches many files over the same TCP connection, but if one packet is lost, all the files have to wait until it’s been sent again. QUIC keeps track of each file separately, so a loss only delays the file it hit. And finally, a QUIC connection can survive the customer moving from Wi-Fi to mobile data in the middle of a purchase, where a TCP connection would have to start over. If you want the technical history from HTTP/1.1 to today, read how HTTP works in detail.
When does it help your store?
The gain is greatest where the connection is worst: on mobile networks with high latency and packet loss, for customers far from the server, and on first visits, when a customer lands from an ad or a search result. On a stable wired connection close to the server, the difference is small.
HTTP/3 also can’t save a page that’s slow for other reasons. If the server is slow to respond, or the browser has to download several megabytes of images and JavaScript, that’s where the gain is. See our guide to images, CSS and JavaScript.
How to check whether your site uses HTTP/3
- Open your site in Chrome or Edge, and open the developer tools (F12).
- Go to the Network tab, right-click the column headers, and turn on Protocol.
- Reload the page. If it says
h3, HTTP/3 is in use. If it saysh2, HTTP/2 is in use.
The browser often uses HTTP/2 on the very first visit and only switches to HTTP/3 afterwards, once the server has said it supports it.
How to turn on HTTP/3
HTTP/3 is turned on at the server or CDN, not in WordPress. If you use a CDN, it’s usually a single setting, and the browser then speaks HTTP/3 with the CDN, whatever your own server can do. Without a CDN, it depends on the hosting: many modern platforms have it on by default, and otherwise it’s a good question to ask when you choose hosting that supports HTTP/3. If you run the server yourself, newer versions of the common web servers support it, but UDP port 443 has to be open in the firewall. HTTP/3 requires HTTPS, and browsers that can’t use it automatically fall back to HTTP/2.
Limitations
Some corporate networks block UDP, and then HTTP/2 is used. HTTP/3 also doesn’t make the server any faster at generating the page. So measure on real users, for example with Core Web Vitals in Search Console, instead of only testing from your own connection.
Frequently asked questions
Do I need to change anything in WordPress?
No. HTTP/3 is handled by the server or CDN, and WordPress, the theme and plugins don’t notice any difference.
Does HTTP/3 affect my ranking in Google?
Not directly. But if it makes the page faster for your visitors, it can improve Core Web Vitals, which Google uses as one of many signals.
Want a faster online store?
HTTP/3 is one piece. We measure all the way from the server to the browser and fix what’s actually making your store slow. Read about our speed optimization for online stores.