A large amount of app development involves integrating with third party systems, typically via an API. More typically via JSON. Paw is a great tool for working with API’s. It’s super simple to create your requests and organise them into groups. I typically group by API call, staging or production, for various testing accounts. It also simply handles authentication.
Paw has code generators which export the ObjC code required for your API call. My workflow currently involves using Cocoa JSON Editor for this purpose. It’s more heavyweight approach will create ObjC classes for object models of the API response.
Using these tools allows you can quickly evaluate an API. They both offer a visual approach to modelling the data and structuring your classes.