The text discusses the growing trend and importance of API startups in the tech industry, emphasizing the significance of APIs being designed with user experience in mind to make them "cool." It highlights that companies like Merge and Stytch are at the forefront of this movement, focusing on building APIs as core products rather than mere extensions of existing systems. These companies prioritize design flexibility and user-developer experience, resulting in APIs that are not only functional but also appealing to both product managers and engineers. The narrative underscores the idea that a "cool" API can influence the longevity and success of tech companies by providing seamless integration and enhancing product development. Merge and Stytch have developed their documentation and client libraries in-house, allowing for more detailed and flexible documentation that aligns with their product offerings. The text concludes by suggesting that the future of successful API companies will be determined by their ability to create APIs that are engaging and user-friendly.