Merge's Unified API offers a streamlined integration solution for B2B companies, particularly in HR, payroll, recruiting, and accounting, by enabling them to sync user data across multiple platforms without extensive engineering resources. Simeon Lee, the Founding Designer at Merge, describes the evolution of the company's API documentation, emphasizing the importance of well-designed, accessible documentation for user success. Initially housed within the company's dashboard, the documentation was later made publicly available, leading to user feedback that prompted significant redesigns to improve information architecture and user experience. These changes included breaking down complex information into manageable sections, enhancing navigation with distinct colors for HTTP methods, and incorporating a search bar to aid information discovery. The goal is to create a seamless integration experience, helping customers integrate efficiently and effectively, which is central to Merge's mission of revolutionizing the API economy.