Ahhh, thank Martin, request template transform was working now.
By the way, the response template seem to be not apply on the response of service. I've used Tyk dashboard to create endpoint API, I've tested on Body transform plugin by providing JSON input, Golang template, which I got the result as my expected when I click "Test".
However, when I call the endpoint on web browser, the service return the original JSON response of target API. I'm not sure why, but I did not see any logging message that Tyk try something on the JSON response. Do you have any suggestion? Should I enable some feature to enable the response processors?