REST (Representational State Transfer)

• Represent data in JSON or XML
• SIX Architectural Constraints
  1. Uniform Interface
  2. Completely Stateless (does not remember about previous request)
  3. Native Caching
     • It is supported by REST-api itself and there is no explicit need of configuration
  4. Client-Server Architecture
  5. Layered System
  6. Ability to provide Executable code to the client
• PROS
  • GET, POST, PUT, DELETE. OPTIONS, PATCH HTTP Methods are used
  • Client & Server are completely decoupled from one another
  • flexible formats (?format=json && ?format=xml) which makes it better for public facing APIs
• CONS
  • No binding contract on what structure is used for messages.
    • Your API sends "100.00" as string, the third party user expects a float 100 value
  • Over-fetching and Under-fetching causing multiple API requests or slowed down response
    • You want only name, id for application but get the entire user data through the API
    • You want name and app-id but you have to make two API calls for user and for app slowing down the process.

Request Methods	Usage
GET	Retrieve Data (Read)
POST	Send Data (Create)
PUT	Usually Replaces entire resource
PATCH	Used for partial Delete
DELETE	Deletes Data (Delete)

Code range	Meaning	Example
2xx	Success	200 - OK 201 - Created 204 - No content (silent OK)
3xx	Redirection	301 - Moved (path changed)
4xx	Client error	400 - Bad request 401 - Unauthorized 403 - Not Permitted 404 - Not Found
5xx	Server error	500 - Internal server error 502 - Bad gateway 504 - Gateway timeout