The multiple IdP dilemma
Having to deal with multiple IdPs is not as uncommon as one may think. Dealing with multiple IdPs can be the result of intended but also unintended design.
As mentioned previously in this chapter, the most notable side-effect of API proliferation is that different teams work in different ways, using different techniques and technologies, and sometimes this means using different IdPs. This is an example of unintended or unwanted IdPs, where a company needs to deal with multiple IdPs not because of a design choice but because of a lack of initial governance. There may be circumstances where multiple IdPs are the result of a design decision. It’s important to understand that collaboration extends beyond the enterprise.
Multiple IdPs are usually involved when an application’s scope spans multiple companies collaborating to achieve the application’s business logic, which needs to harness features provided by external APIs or applications...