Explore the world of open-source local large language models (LLMs) in this 40-minute conference talk from Devoxx. Dive into a comparative analysis between these models and proprietary giants, focusing on their performance, flexibility, and applicability in developer applications. Gain valuable insights into the impact of model size on performance, the potential for fine-tuning models for specific projects or coding languages, and the benefits of utilizing local open-source models over commercial alternatives. Discover practical considerations for selecting and implementing LLMs in development environments, with emphasis on data privacy, cost-effectiveness, and customization options. By the end of this talk, acquire a comprehensive understanding of the current landscape of LLMs and their implications for developers.