The blog post discusses the importance of planning and designing APIs and microservices effectively when using the Kong API Gateway, highlighting the distinction between APIs and services within this context. Kong, an open-source API management platform, is capable of managing services across multiple protocols such as HTTP, gRPC, GraphQL, and TCP, making it essential to define a key entity known as a Service. A Service in Kong represents upstream services and can include examples like data transformation microservices or billing APIs. The post explains that Routes in Kong define rules to match client requests and are linked to Services, ensuring that requests are proxied appropriately. It emphasizes using tools like Insomnia Designer for API design, which allows users to configure Services and Routes and suggests trying out the declarative config plugin for automating the generation of these entities from an OpenAPI Specification.