I'm trying to integrate with the Salesforce Marketing Cloud using API Integration from the App Center. Basically, we have multiple clients in our platform who wishes to push data into their ExactTarget account.
After reading through most of the documentations, I feel like this is not possible with API Integration since it's one app to a business unit. I was hoping to have our clients authenticate through our account, but the API looks like it doesn't return an ID etc.
What's an alternative? Would creating a package work better for this scenario instead?