Microsoft.Extensions.AI vs Semantic Kernel: What Is the Difference? If you're building AI applications with .NET, you've probably encountered two Microsoft technologies that appear to overlap: Microsoft.Extensions.AI Semantic Kernel Both can be used when building applications that communicate with large language models, work with tools, generate structured responses, retrieve information, and implement AI-powered workflows. That naturally leads to an important question: Are Microsoft.Extensions.AI and Semantic Kernel alternatives, or do they solve different problems? The most useful answer is that they operate at different architectural levels . Microsoft.Extensions.AI provides common .NET abstractions and building blocks for AI services. Its ecosystem includes abstractions such as IChatClient , IEmbeddingGenerator , AI functions, tool support, and chat-client pipelines. Semantic Kernel is a broader AI development SDK centered around the Kernel , ...