In order to leverage external domains inside your function(s), you'll need to whitelist them. This can also be done in the Settings section. We have a proxy in place which will check incoming requests from functions and see if the requested URL is whitelisted.

Within the lp-faas-toolbelt, we provide a method that generates the required headers for communication with the proxy. A detailed explanation on how to use this feature is shown here.

Please make sure to whitelist the fully qualified domain name. E.g. If you visit the server will actually redirect to, which means the domains you need to whitelist would be and

Generally, we will prevent the double whitelisting of a domain. The UI will also indicate that this occurred using a dedicated error message. We also perform validation on the provided domain in order to ensure it is a valid domain name. For now, we do not support the whitelisting of subdomains such as

Please be aware that it might take up to 5 minutes until the whitelisted domain becomes active on the proxy.