A REST API works by breaking down an activity. This generates a sequence of small components, while each component will tackle a specific part of the activity. Flexibility is allotted from this component, but challenges can certainly arise. REST APIs use prevailing HTTP procedures. They use GET to get back a resource; PUT to change the state of the API or modernize a resource. All API calls are stateless. This means that nothing can be held by the RESTful service between implementations.