LLM Builder Kit - Hands-On LLM

Now with 10 chapters, quizzes, achievements, and a searchable glossary. Build, train, and compare your own language models — no coding required.

Ever wondered how AI chatbots like ChatGPT, Gemini, Claud actually work under the hood? LLM Wizard lets you build a real language model from scratch — on your phone. Whether you're a curious beginner or a seasoned developer, this app walks you through every fundamental concept powering modern AI: tokenization, n-gram probabilities, training epochs, loss curves, temperature sampling, fine-tuning, and prompt engineering. Learn Mode — 10 interactive chapters:

Understand how raw text becomes a trained model, step by step. Visualize attention weights, explore embeddings, and interact with a live language model as you learn. New in v2.0: chapters on Fine-Tuning & RLHF and Prompt Engineering take you all the way to how today's AI assistants are built. Build Mode — 6-step wizard:

Choose your own domain (fairy tales, movie reviews, cooking, sports, poetry, and more — or paste your own text), configure your tokenizer and hyperparameters, watch your model train in real time, then generate text with your finished model. Save snapshots and compare two models side by side. Test yourself:

Take a quiz after every chapter, unlock 12 achievements, and track your progress through the full curriculum. Glossary:

50+ searchable definitions covering every LLM concept in the app — always one tap away. No cloud. No API keys. Everything runs on-device. Perfect for students, developers, educators, and anyone curious about how AI really works.