Either, and you choose per engagement. Your team can build the atom library and hand it over, or run it on the client's behalf as part of a retainer. Because roles and approvals control who can publish, a client can review before anything goes live even when your team does the writing.
This is one atom from the Spectare content library. Spectare assembles the right atoms for each visitor in real time, based on who they are and how they arrived.