AWS Signature API testing is a type of software testing that performs verification directly at the API level. It is a part of integration testing that determines whether the APIs meet the testers’ expectations of functionality, reliability, performance, and security. Unlike UI testing, API testing is performed at the message layer without GUI.
There are two broad classes of web service for Web API: SOAP and REST. SOAP (Simple Object Access Protocol) is a standard protocol defined by the W3C standards for sending and receiving web service requests and responses. REST (REpresentational State Transfer) is the web standards-based architecture that uses HTTP. Unlike SOAP-based Web services, there is no official standard for RESTful Web APIs. https://goo.gl/E6dpsN
