Navigating the world of ArcGIS Online and Portal can often be tricky. How does one balance the named users for each account while minimizing cost and creating a healthy return on investment for the company stakeholders? Each program has a set of allowable named users per software license. ArcGIS Online offers subscriptions in groups of 5, 50, and 100 that can be disparaging when you have a company that needs more than 5 but less than 50 named users. ArcGIS Server accounts come with 50 named users per server license with the option to purchase more at 5 user increment. So it seems logical to try to go through your Server to have members access the data they need for work.
So how does one go about sharing this data the most cost effective way? The answer is to combine ArcGIS Online and Server by publishing your data publicly from a feature service stored on your server and locking it on the Server Manager side using groups and roles. This creates a secured public feature service that is restricted to your named users in Server.
So how exactly does that work? Once you have created the map or decided on which features you want to share, you publish them through desktop to your server into a new folder. In Server Manager create a custom role and give them a descriptive name such as Secured Public and then add all the users who will need to be a part of that role into that role. Once you have defined the users and created the role you can then lock the service at the folder level through service security to be able to only be viewed by members of your named user Server account. Then you go to your REST API, where your features are hosted and get the URL of that particular service. Once you have the URL you can add the feature via ArcGIS Online by selecting the option to add an item from the web. Once you have added the item into your ArcGIS Online account, you share the item publicly. The restriction calls for the user to log in when accessing the feature because it is hosted by your server and not ArcGIS Online.
By using this workflow you can save money by not having to increase your ArcGIS Online named user number of accounts. You can access the benefit of the public viewing configuration available through ArcGIS Online but still configure your features to be securely locked down per specific user granted access. Another great benefit to establishing your feature services this way is that since the Server is hosting your data you save money on credits by not using up additional storage.