App42 platform has various technical and business services using which app development can be done without writing a single line of backend code. However there might be a case where the app developer might need to have some server side custom code for their app. There could be multiple scenarios for example- You want to add server side validation and or custom logic on the input data instead of on the client. You want to make a custom service by aggregating two or more App42 services. For example aggregating Push and Storage service for custom requirement. App logic that might get changed in future and hence you don’t want to bundle it in your app. Instead you would like to put it on the server where it can be accessed through REST calls from your app.