You can use the path used in the DarkSky API when access the API via Tyk too.
For example, if you define your API upstream target as
https://api.darksky.net/, and have an API slug as
weather, then you can access it through the Tyk Cloud as
Tyk will identify the API by the
weather element of the path, then take the remaining of the path
forecast/37.8267,-122.4233 and add that to the target URL to make