For such backend services, you need a way to cut off external traffic so that they are only accessible within WSO2 Integration Cloud and API Cloud but not to the public internet.
Today we are releasing an Integration Cloud feature that lets you selectively open or close public internet access to your applications.
To hide your application from the internet, simply:
1. Open the application in WSO2 Integration Cloud.
2. On the left-hand menu, click Settings.
3. On the Exposure Level tab, click Private:
Once you click the Update button, the application will no longer be accessible from the internet. You will only be able to access it within WSO2 Integration Cloud and WSO2 API Cloud using the *.wso2apps.local URL.