For an enterprise, what is the recommended approach for API portals?
I think that depends on the nature of your API itself...
- If the internal and external developers consumer the same APIs (lets say Retail APIs) and you intended to show different sets/levels of content to different types of developers, having one portal with different access levels will help. It will 1. Help you to treat the API the same way, have same SDLCs etc 2. Have low friction to promote APIs from internal to external etc.
- If the APIs are fundamentally different (like SDN APIs for internal developers and Telephony APIs to external developers), having different portals for each one of them is better.
Basically one portal per API Program is probably better.
But again, there could be lot of other factors and internal processes of your enterprise that you might have to consider.
You might also consider some of the ideas here https://community.apigee.com/articles/23210/coordinating-api-and-app-development-cycles.html