An API stands for application programming interface, can be written in any language. An API is a set of verbs by which applications interact with each others.
As an API use a predefined set of verbs, we can call it a Restful API (Representation State Transfer).
When accessing an API. That API will return a response in JSON (JavaScript object Notation) format.
JSON is lightweight format for transporting data.
CRUD operation are used for creating, reading, updating and deleting data. An HTTP (Hypertext Transfer Protocol) method is used to POST, GET, PUT and DELETE data.
Performing an operation (HTTP request) will result in a response code or status code. Status code could be :
1xx – Informational
2xx- Success
3xx- Redirection
4xx – Client error
5xx – Server error