Generative AI with C#: OpenAI SDK and Gemini

Generative AI with C#: OpenAI SDK and Gemini

A Practical Guide for .NET Developers

Generative AI is rapidly becoming part of modern software applications, and .NET developers can build these solutions using the C# skills they already have.

This practical guide takes you from your first AI API call to production-oriented concepts such as RAG, AI agents, MCP, security, evaluation, observability and voice AI, with complete C# examples.

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🚀 What You'll Learn

• Understand LLM fundamentals, tokens, context windows, prompts and temperature
• Make your first AI calls using the OpenAI SDK for C#
• Work with Gemini from C# using compatible APIs and HttpClient
• Write better prompts and use few-shot examples
• Generate reliable structured JSON output
• Allow AI models to call your C# functions and tools
• Create embeddings and perform semantic search
• Build a complete Retrieval-Augmented Generation (RAG) pipeline
• Understand and work with vector databases
• Build AI agents that can plan, act and check their work
• Build and connect MCP servers and clients
• Protect AI applications against prompt injection and data leaks
• Evaluate AI application quality with practical measurements
• Add logging, metrics and tracing to AI applications
• Work with images and documents using multimodal AI
• Build speech-to-text and text-to-speech applications
• Understand fine-tuning and training data
• Learn the essential mathematics behind modern ML systems
• Understand how large language models are trained

📚 Why This Book?

This book is written specifically for C# and .NET developers who are new to Generative AI.

You do not need a machine-learning background or advanced mathematics. Each topic is explained in simple language and followed by practical C# examples that you can run, modify and experiment with.

Each chapter follows a simple learning approach:

1. What is it?
2. Why do you need it?
3. Where is it used?
4. How does it work?

👨‍💻 Who Is This For?

• .NET and C# developers entering Generative AI
• Software engineers building AI-powered applications
• Backend developers working with ASP.NET Core
• Developers preparing for AI engineering interviews
• Architects exploring RAG, agents and MCP
• Developers who want practical C# examples instead of theory-heavy explanations

🛠️ Topics Covered

📖 What's Inside

The book contains 19 chapters organized into five parts, covering everything from LLM fundamentals and API integration to RAG, vector databases, agents, MCP, production safety, multimodal AI, voice, fine-tuning and the mathematics and training behind LLMs.

🎯 Build Practical AI Skills

The goal is not just to understand Generative AI concepts. You will learn how to apply them in real C# applications through practical examples, projects, interview tips and self-check questions.