This document discusses REST (REpresentational State Transfer), which is an architectural style for distributed hypermedia systems. It describes REST's six guiding constraints and four interface constraints. It also discusses the RESTful methods POST, GET, PUT, and DELETE. Additionally, it covers JSON (JavaScript Object Notation), which is a commonly used data format for data interchange with REST APIs. JSON supports basic data structures of objects and arrays. The document contrasts that while JSON is a common format for REST, REST itself can support other formats as well.