I know it's been a while since this was posted but here's my solution. Windows 10/11 come with curl.exe (cmd or powerShell) installed by default so you don't need to install/develop another app. You can use either IPC as suggested above or any a native SKILL command (e.g. axlRunBatchDBProgram) to launch a HTTP POST. My tested commands (call curl.exe in cmd), for JSON strings values, with all security disabled (safe environment in my case) looks like this:

In your SKILL code, assign the below string to the variable CommandString (sorry for not posting the complete syntax, I am compiling from multiple TCL and SKILL files and I am sure I'll miss some "" on the way)

curl.exe -v --insecure --ssl-no-revoke -H "Content-Type: application/json" -X POST https://www.google.com/ -d "{"var1":"value1","var2":"value2","var3":"value3","var4":"value3"}"

axlRunBatchDBProgram("start cmd /c ", CommandString ?noUnload t ?silent t ?noProgress t ?noLogview t ?warnProgram t ?noExitMsgs t)