Universal APIs, also known as unified APIs, offer an aggregated solution for building multiple integrations between a product and third-party software within a specific category, streamlining processes such as user provisioning, compliance tasks, and gift-giving workflows. The text explores the benefits of using universal APIs, emphasizing that they provide competitive differentiation, facilitate upselling, empower engineers to focus on core initiatives, enhance employee experience, improve customer retention, and aid in market expansion. Merge is highlighted as a key player in this field, offering several unified APIs across various software categories like HRIS, ATS, CRM, and more, while also providing integration management capabilities that alleviate the burdens of maintaining client integrations. The guide suggests criteria for selecting a universal API platform, including reviewing the platform's range of APIs, data synchronization capabilities, integration management features, and third-party reviews to ensure they meet evolving integration needs.