RESTlets allow us to build custom REST-based endpoints into NetSuite; thus, RESTlets form the backbone of nearly any integration into NetSuite.
RESTlets provide individual event handlers for four of the most commonly used HTTP request methods:
GET
POST
PUT
DELETE
When a RESTlet receives a request, it will route the request to the appropriate event handler function based on the HTTP request method used.
Authentication to a RESTlet can be done via user session, HTTP headers, or OAuth tokens.