Session layer design patterns

I am planning to build an app that will mainly fetch data from different services and display them to current logged in user.

The thing is that all the data that I fetch from three different api's I am not allowed to store them in database, so I will have to use session in that case.

My question is :

Does anyone has a suggestion on how to design a scuh application, is there any specific >design pattern that is based on session that I could possibly follow ?