TokenLab - Build & Train LLMs

TokenLab teaches you how modern language models work by letting you build, train, evaluate, and use small models directly on your iPhone. Follow an 18-module learning path that begins with machine learning foundations, tokenization, embeddings, attention, and transformer architecture. Continue into model training, fine-tuning, alignment, reinforcement learning, preference optimization, RAG, agents, evaluation, on-device optimization, embodied AI, and robotics. LEARN BY DOING - Each lesson combines concise technical explanations with: - Interactive diagrams and model controls - Worked examples grounded in real training concepts - Knowledge checks designed to test understanding - Guided experiments that connect theory to measurable results - Reference materials and saved lessons for later review TRAIN MODELS ON DEVICE - Use the Training workspace to conduct real micro-model experiments on supported iPhones: - Train a tiny transformer from scratch - Adapt a pretrained model with a compact adapter - Create and edit training datasets - Configure model size, context length, learning rate, steps, and sampling - Track training and validation loss - Inspect generalization, latency, memory, and test results - Save local checkpoints and compare previous runs - Stop experiments manually or automatically when device conditions require it EXPERIMENT IN PLAYGROUND Chat with the pretrained model or select one of your saved checkpoints. Compare how training decisions affect model responses and return to earlier conversations when testing new ideas. Playground conversations and model checkpoints are stored locally and can be deleted from within the app. APPLY EACH MODULE IN A LAB Guided labs turn concepts into structured experiments. Work with validation splits, tokenizers, model architecture, adapters, retrieval, evaluation, robotics policies, and other practical workflows. TRACK REAL PROGRESS - Build a visible record of your development through: - A structured skill tree - Module and lesson completion - Lab results - Mastery checks - Experience levels and weekly missions - Saved experiment history DESIGNED FOR SERIOUS LEARNING TokenLab is built for developers, students, technical professionals, and anyone who wants to understand what happens inside a language model. The interface supports Light and Dark Mode and follows your iPhone’s system appearance automatically. Lesson progress, assessments, and training records can sync securely to your TokenLab account. Model execution takes place on device. TokenLab’s micro models are designed for education and experimentation. They are not intended to replace production-scale language models.