Check that your website is served over HTTP/3

Websites hosted at SwissCenter are now served over HTTP/3, the latest version of the protocol that carries web pages between the server and your visitors' browsers. HTTP/3 runs on QUIC: connections are set up faster and cope better with packet loss, especially on mobile networks and unstable Wi-Fi.

Prerequisites

A website hosted on our servers, served over HTTPS with a valid SSL certificate: HTTP/3 only works over an encrypted connection.

Good to know before you start

There is nothing to enable: HTTP/3 is offered automatically to every visitor over HTTPS.
The server announces it to the browser on the first visit, which still uses HTTP/2; the browser switches to HTTP/3 on the following visits.
If the visitor's network blocks QUIC (some corporate firewalls), the browser falls back to HTTP/2 on its own, with no error and no interruption.
Your website, your .htaccess and your applications (WordPress, Joomla…) work as before: only the transport changes.

Check that your website answers over HTTP/3

Open http3check.net in your browser.
Enter your domain name without https:// (for example votresite.ch), then click CHECK. You can also open https://http3check.net/?host=votresite.ch directly, replacing votresite.ch with your domain.
The test succeeds when both lines QUIC is supported and HTTP/3 is supported are shown in green.

You can also see it in your browser: open the developer tools (F12 key), Network tab, show the Protocol column and reload the page; requests to your website show h3.

Troubleshooting

The test fails or only shows HTTP/2: check that your website opens over https:// with a valid certificate. Without a certificate, install one from the Apanel console.
Your domain goes through a third-party service (Cloudflare or another proxy): the test reaches that service, not our servers. The result then depends on its settings.
The test succeeds but your browser shows h2: this is normal on the first visit, or if your network blocks QUIC. Reload the page, or test from another connection (your phone's hotspot, for example).