Regarding your button question: You do need some sort of seam at the point of use so that the feature flag logic can be hidden behind a lookup function. For ex

Regarding your button question: You do need some sort of seam at the point of use so that the feature flag logic can be hidden behind a lookup function. For example in Rails you might include your button code via a partial template. You could use a view helper to provide the name of the partial and that helper could respond with different names depending on the feature flag: <%= render partial: primary_button %> def primary_button feature_flag_enabled ? "new_button" : "button" end Obviously the particulars are going to be different in different frameworks.