Many proxy tools could change the HTTP response from an HTTP request. This type of data change can be very seductive, but it is not a good practice.
Some development teams have rigidly defined organizational structures. In this type of scenario, the proxy is something that belongs to Ops or DevOps. Therefore, proxy level changes can be bureaucratic and any modification to the response in an inappropriate way will generate collateral damage that is difficult to detect and alter.
The best practice is to always control the content of the response at the application level, not delegate that task to the proxy.