When we develop a Single Page Application, we have to use a Router. It's a common use case, yet every single framework has its own router, React even has multiple ones you can choose from. And even though each framework is different and every router takes a different approach, they all share quite a few principles. Understanding those helps us handle routing in our SPA because behind all those simple, different APIs provided by framework-specific routers, a more complex architecture is hidden from us. Eduardo dives into the architecture of a Router and some of its implantation details.