One Pager Cheat Sheet

• We can learn about HTTP request and response by deconstructing each of its components, such as the verb (a.k.a. method) with associated headers and an optional body, and understanding web server behavior, which is stateless.
• An "Unauthorized" request error can occur when the client does not include an Authorization header in the HTTP request, resulting in an error with a status code in the range 400-499, indicating a client error.
• RPC and REST are two prominent approaches to distributed API design over the past few decades.
• RPC (Remote Procedure Call) is a way to call a function on a remote server, which uses GET to fetch data and POST for everything else, and is good fit for APIs that are based on actions.
• The RPC protocol uses POST for all calls that make updates to the server, while REST generally follows the conventions of using GET, PUT, PATCH, and DELETE for modifications.
• REST is an architecture style for creating stateless, cacheable, HTTP-semantic client-server APIs that enable CRUD operations on resources, expressed with unique URLs and HTTP verbs.
• No, REST and RPC are not interchangeable, as the HTTP verb used for each of them has a different purpose with regards to the type of operation.
• When deciding between RPC and REST for an API, consider if it's mostly actions or structured data - and if it's both, it's OK to use both styles!
• RPC APIs, such as PlaceOrder, are used to perform a certain action when a specific event occurs.