Proprietary model
Also known as: closed model · closed-source model
A proprietary (closed) model is one you can only use through the provider — its API or app. The weights never leave the company; you send text in, get text out, and never touch the model itself.
This is the default for the biggest names (GPT, Claude, Gemini as APIs).
- Pros: you get the strongest models, hosted and maintained for you.
- Cons: per-token cost, data leaves your machine, and you’re bound by the provider’s terms.
The choice you'll keep making: proprietary (powerful, hosted, paid) vs open-weights (private, local, free-ish). Both are legitimate — they're different tools for different constraints.