AI Glossary / Model weights

🏗️ Models and training

Weights are the concrete values of all parameters of a trained model - in practice, large files of numbers that are the entire "knowledge" of the network. Whoever has the weights can run the model on their own hardware, modify it, and fine-tune it. Hence the fundamental market division: closed models (available only through the producer's API, like GPT or Claude) and open-weight models (like Llama, Mistral, or DeepSeek) that can be downloaded and self-hosted. Open weights don't always mean full open source - licenses vary.