Most web traffic today is driven by API calls between web applications and RESTful APIs. A RESTful API allows endpoints to integrate with each other in accordance with business logic built into the API, enabling microservices to work together like a traditional monolithic application. REST stands for Representational State Transfer, defined by 6 constraints: client-server, stateless, cacheable, layered system, uniform interface, and code on demand. A RESTful API defines a set of functions that developers can perform requests and receive responses via HTTP protocol such as GET, DELETE, and POST. Resources can be called upon singularly, making it possible for mobile apps to continue providing expected functionality while select components are being edited or improved. The use of RESTful APIs has become essential in today's apps and games that provide top customer experience by employing short release cycles and microservices powered by REST APIs to maintain high levels of code reliability, resilience, and efficiency throughout iterative changes.