HTTP/2 processes browser requests more efficiently than HTTP/1.1, which usually means noticeably faster page loading — particularly on pages that pull in many separate files.
Requirements
- Nginx as the web server. For OpenLiteSpeed, HTTP/2 support is enabled by default.
- An SSL certificate issued and enabled for the site. HTTP/2 only works over HTTPS — there is no way to use it on a site served over plain HTTP.
Enabling HTTP/2
Go to Web server settings and tick Enable HTTP/2.
It is then activated automatically for every site that has a working SSL certificate. Sites without a certificate continue to be served over HTTP/1.1 until one is issued.
Note that this is a server-wide setting and requires administrator or reseller access to the panel. If your account does not have it, open a ticket and we will enable it.
If a site is still on HTTP/1.1
Almost always the certificate is the reason. Check that the site opens over https:// without warnings and that the certificate is enabled for that particular domain — a certificate covering example.com does not cover www.example.com unless that name was included.
You can check which protocol is actually in use in the browser's developer tools, on the network tab: the protocol column shows h2 for HTTP/2.
Worth knowing
Older optimisation techniques designed to work around the limitations of HTTP/1.1 — combining many small files into one, or spreading assets across several subdomains — bring no benefit under HTTP/2 and can even work against it. If your site was built with those techniques, it is worth reviewing them.
If HTTP/2 is not working after the certificate is in place, open a ticket from your client area with the domain name.
