Confused by the hundreds of AI models available? Not sure when to use GPT-4.1 vs o4-mini? In this comprehensive lesson from Nemesis Courses, we break down exactly how to choose the right Large Language Model (LLM) for your application and how to integrate it into your code. We start by analyzing the critical criteria for model selection—reasoning, speed, cost, and context window. Then, we dive into the OpenAI Playground to master settings like Temperature and JSON mode. Finally, we open VS Code to build a real application using the OpenAI SDK, covering everything from API keys to streaming responses. In this video, you will learn: 🚀 Model Selection Framework: How to balance cost, speed, and intelligence. 🎛️ Model Parameters: Mastering Temperature, Top P, and Max Tokens. 📋 JSON Mode & Schemas: How to get structured data output every time. 💻 OpenAI API Integration: Setting up the official JavaScript SDK. 🌊 Streaming: How to stream responses in real-time (like ChatGPT). Timestamps: 0:00 - Introduction 0:30 - How to Choose the Right AI Model 1:30 - Cost & Context Windows Explained 2:20 - Comparing OpenAI Models (GPT-4.1, o4-mini, o3) 5:00 - Mastering Model Settings (Temperature & Top P) 6:05 - JSON Object vs. JSON Schema 10:40 - Max Tokens & Troubleshooting Cut-offs 13:41 - Coding with the OpenAI API ( Setup) 17:41 - Implementing Response Streaming #NemesisCourses #OpenAI #WebDevelopment #OpenAI #NodeJS #GPT4 #AIProgramming #WebDevelopment #SoftwareEngineering #LLM #CodingTutorial #NemesisCourses #APIIntegration