Merge offers Unified APIs that simplify integration development for B2B organizations, providing a single endpoint for semantically similar integrations like CRM and HRIS. Initially relying on OpenAPI's SDK Generator, Merge faced challenges with fragmented and error-prone SDKs. Switching to a Fern-based SDK workflow allowed Merge to efficiently automate code generation, creating robust and well-documented SDKs while maintaining human oversight for final code deployment. This transition led to cleaner, more readable SDKs, improved documentation, and support for both synchronous and asynchronous requests across multiple programming languages. Fern's approach also enhanced Merge's backward compatibility and support for polymorphic code, allowing the company to focus on its core API product. The adoption of Fern resulted in a more consistent and high-quality experience for developers using Merge's SDKs, as reflected in positive customer feedback.