Modify server response in ios native app automation testing

Could you help me? I have java + selenium + appium project for automate testing native app on ios. In common cases all works fine. IPhone simulator creates, test runs successfully. But in some cases I need to modify response from server. And I searching for some proxy api that can do it. I was trying to use BrowserMob-Proxy, but no result. Maybe I doing something wrong. Can anyone give me advice of using that or another api? If you can give a full example of code - it will be great!