I guess I have more questions about what you are trying to achieve -
Do you require the information retrieved from your external HTTP API to be available as data points / point values? (e.g. you want to store history for them in the Mango time series database, or you want the values to be available on the watch list etc) Is the external HTTP API available on the internet / accessible from the client web browser? If so you may be able to request the data directly from the web browser via a XHR request.