API testing is an integral part of the development process that evaluates an API's functionality, reliability, performance, and security, targeting the application's business logic layer. The primary goals of API testing are verifying the API's functionality, assessing its reliability and stability, evaluating its performance, identifying and addressing security vulnerabilities, verifying adherence to an API contract, and ensuring high-quality code deploys to production by allowing teams to identify and fix issues early in the development lifecycle. A good API testing tool should support automated testing capabilities, test scenario management, integration with CI/CD pipelines, advanced features such as mocking and virtualization, robust debugging capabilities, and isolation of development and production environments. Tools like Blackbird aim to simplify and accelerate the way developers create and test APIs by providing powerful mocking, debugging, and environment management capabilities.