Glossary · Phase 1 · Building with LLMs

Open-weight model

Also written: open model, open models, open-weight models, open weights

A model whose weights are published, so you can download and run it yourself.

Try it now

Using the prices in this lesson. Output costs five times as much as input, so watch how much the output slider moves the total.

Choosing a model · Trade capability, speed and cost across model families. About 25 minutes.

closed model: A model you can only use through its maker's API: you can't download its weights or run it yourself.
fine-tuning: Further training a pretrained model on a smaller, focused set of examples to change its behavior.

Teach a small one to write, right in your browser. It takes about 20 seconds and needs no account.