General case
Gluer retrieve sites configurations at startup from the Registry and get notified of updates and new site configurations.
On an incoming request, Gluer will go through each configuration to find a domain that match.
A Site configuration may be an Experience (overide of a default site config)
Special case of Designer
When using the Designer, it will send the header X-Kobi-Site-Id to force the Site resolution.
Designer will identify itself on Gluer with
X-Kobi-Authorization header to be able to use special headers
Device detection
Once the site is identified, Gluer will take the first device where User-Agent header from the incoming request match with the configured regex in the device list of your Site configurations.
Check the User guide for more detail on these properties