API stands for Application Programming Interface, a software code that helps two applications to interact and exchange data. Learn about different types of APIs, web APIs, API testing tools and applications of API with examples and diagrams. An API (application programming interface) is a set of rules that allows software applications to communicate and exchange data or functionality with each other. A Web API or Web Service API is an application processing interface between a web server and web browser. All web services are APIs but not all APIs are web services. REST API is a special type of Web API that uses the standard architectural style explained above. The different terms around APIs, like Java API or service APIs, exist because historically, APIs were created before the world wide web. Modern web APIs are REST APIs and the terms can be used interchangeably. API (Application Programming Interface) testing is a kind of software testing that analyzes an API in terms of its functionality, security, performance, and reliability.
