Have you used tools for documenting REST API (Swagger/OpenAPI)?

Yes, I have used Swagger/OpenAPI for documenting REST APIs. It allows for automatic generation of interactive documentation, which makes it easier to understand and test the API for both developers and clients.

Example of usage with Spring Boot:

import io.swagger.v3.oas.annotations.OpenAPIDefinition;
import io.swagger.v3.oas.annotations.info.Info;

@OpenAPIDefinition(info = @Info(title = "Example API", version = "v1"))
@SpringBootApplication
public class Application {
    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }
}

This allows for automatic generation of the OpenAPI specification, which is accessible via a UI, such as Swagger UI, for convenient interaction with the API.