What is Open-Weight Model?

Open-Weight Model, explained

With a closed model, users can access it only through the provider's app or API. An open-weight model releases the weights themselves, so organizations can run the model on their own servers or devices, fine-tune it, and inspect its behaviour more directly.

Open-weight is not always the same as open source. Some releases share weights but not the training data or code, and some licences limit commercial use or very large deployments. A healthcare software company might choose an open-weight model so patient data never leaves its own infrastructure. The trade-offs include the cost of hosting and maintaining the model, responsibility for security updates and safety controls, and performance that may trail the most capable closed models on complex tasks.