Discord Webhook

Most apis are https only for security reasons (not sending the auth credentials in plain text keeps them from having to deal with support tickets related to snooped credentials)

Unsecure hacks like this are going to be standard up until byond gets native https support, as well as http method and header support.

In current byond, its impossible to use most apis.

Still, the server sends url to client to execute js script.

While the request to discord api is executed by the client, client can intercept and analyze this request with some special programs.

Another variant is perhaps get address by manipulating client's cache/skin. In the demo though it's hard to achieve, but in some cases it is still an option.

It's better to use for this some server side script with shell() or library with call()

It's not a good idea to give client an hook url. Knowing the address client can abuse it.