# Introduction
Artificial Intelligence is changing how we write, search, and build software. Large Language Models (LLMs) are at the center of this transformation. They can understand text, answer questions, write code, and even reason about problems. Most developers think that creating an LLM requires deep math knowledge or powerful cloud infrastructure. But the truth is – you can start right where you are, using only PHP.
This book, *Build Your Own LLM with PHP*, is a complete journey into building and understanding your own language model using nothing but PHP. You will not depend on external AI services or heavy Python frameworks. Instead, you will see how far PHP can go on its own when it comes to working with text, numbers, and knowledge.
We will build everything step by step – from tokenization and vector math to embeddings, similarity search, and lightweight reasoning. You will learn how to create and train components of your model, store and query information efficiently, and make the system respond intelligently to questions.
By the end of this book, you will not just understand how an LLM works. You will have created one yourself – written fully in PHP, simple, transparent, and entirely yours.
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