The text provides an in-depth guide on fine-tuning open-source GPT models using domain-specific web data, emphasizing the limitations of prompt engineering and retrieval-augmented generation (RAG) for creating specialized models. It outlines the benefits of using continuously updated and diverse web data for fine-tuning, as it enhances the model's ability to handle varied input types and reduces bias. The text also details the process of collecting, preparing, and fine-tuning web data using tools like Bright Data's scrapers and APIs, highlighting the importance of structured data preparation and balancing domain-specific with general data. Additionally, it discusses choosing a suitable base model for fine-tuning, depending on factors like data type, task complexity, and budget. The guide includes a practical example of fine-tuning a Llama 4 model with product data from Amazon, illustrating steps from data collection to deploying the fine-tuned model, and emphasizes the importance of efficient resource management, iterative refinement, and proper deployment workflows.