The Copilot era has begun and it’s time to put our Generative AI knowledge at work in our apps. There is a clear benefit in providing the Copilot capabilities inside an application in contrast to the generic ChatGPT. Your application can provide the topics context that makes a huge difference and we will see the reasons to better fine-tune the results. In this application we will see some user cases going from classification to semantic search and RAG, going through recommendations and summarization. But overall, we will see in practice what are the building blocks to build an efficient Copilot in .NET, using online services or offline models and vector databases to fully control the data knowledge and costs.