Answers

1. RESTful services became popular because they work on top of HTTP, which is the backbone of the internet. You don’t need separate protocol implementations such as SOAP. You can use existing web technologies to implement the REST APIs with simple application integration compared to other technologies available. REST APIs make application integration simpler than other technologies available at the time.

RESTful services work on REST, which works on web resources. Resources represent domain models. Actions are defined using HTTP methods, which are performed on web resources. REST also allows clients to perform actions based on links available through HATEOAS implementation, like a human who can navigate in the browser.

2. RPC is more like functions that perform actions. RPC endpoints are directly formed based on verbs that lead to separate URLs for each action. Whereas REST URLs represent nouns and could be the same for different operations, for example:

   RPC: GET localhost/orders/getAllOrdersREST: GET localhost/orders
   RPC: POST localhost/orders/createOrderREST: POST localhost/orders

3. With HATEOAS, RESTful web services provide information dynamically through hypermedia. Hypermedia is the part of the content you receive from a REST call response. This hypermedia content contains links to different types of media such as text, images, and videos. Machines, aka REST clients/browsers, can follow links when they understand the data format and relationship types.
4. Status code 500 should be used for generic server errors. The 502 status code should be used when an upstream server fails. Status code 503 is for unexpected server events such as an overload.
5. Verbs should not be used to form REST endpoints. Instead, you should use the noun that represents the domain model as a resource. HTTP methods are used to define the actions performed on resources, such as POST for creating and GET for retrieving.