A REST API is a standardized software architecture style for building web services that perform CRUD operations on data using HTTP requests. RESTful services are easy to build and consume, and they follow the precepts of the web, including its architecture, benefits, and everything else. Spring Boot is a powerful framework that makes it easy to create RESTful APIs. To create a REST API in Spring Boot, you need to set up your development environment, create a new Spring Boot project, and configure it for your needs. You can use annotations like @RestController and @RequestMapping to specify the base URL for all requests handled by the controller. You can also use @RequestBody to bind the HTTP request body to a parameter in a controller method. Finally, you can test your REST API using tools like Postman.