Also called: open model, open-source AI · Last checked: 7 November 2026
In short: An open-weight model is an AI model whose trained settings, called weights, are published for anyone to download. A business can run it on its own servers, change it and avoid paying per use.
Table of Contents
How it works
- Release. A lab trains a model and posts its weights online, usually with a licence that sets the rules for use.
- Download. A business copies the model to its own servers or a cloud account.
- Adapt. Developers can fine-tune it on their own data and run it without sending data to the original lab.
Where you’ll meet it
Meta’s Llama, Mistral’s models, Alibaba’s Qwen and DeepSeek are well-known open-weight models. ChatGPT’s main models are closed, though OpenAI also released open-weight models in 2025.
What it means for your business
- Lower running costs. Once hosted, you pay for computing power, not a fee per question.
- Data stays with you. Running the model in-house keeps customer data off outside servers.
- You own the upkeep. Your team, or a supplier, must host, secure and update the model.
Watch out for
- Licence limits. Some licences restrict commercial use or very large companies, so read the terms.
- Origin questions. Customers and regulators may ask where a model came from, especially for models built abroad.
- Fewer guardrails. Safety filters can be weaker or removed, so add your own checks.
Example
Airbnb. In October 2025 Airbnb’s chief executive Brian Chesky told Bloomberg that its customer service agent relies “a lot” on Alibaba’s open-weight Qwen models, which he called fast and cheap. He said the agent draws on 13 models in total. He also said Airbnb did not use OpenAI’s latest models much in live service, because faster and cheaper models were available.
Open-weight model vs frontier model
| Open-weight model | Frontier model | |
|---|---|---|
| What it is | A model anyone can download and run | One of the most capable models available |
| Access | Your own servers or any cloud | Usually through the maker’s app or API |
| How they relate | Can be frontier, but often a step behind | Mostly closed, though some are open |
Frequently asked questions
Is an open-weight model the same as open source?
Not quite. Open source usually means the training code and data are shared too. Most open-weight models share only the weights, under licences that may limit use.
Are open-weight models free?
The download is usually free, but running them is not. You pay for servers or cloud computing, plus the staff or supplier who sets up and maintains the model.
Which tasks suit an open-weight model?
High-volume, routine work such as sorting tickets, summarising or drafting replies. It also suits work where data must stay in-house for privacy or legal reasons.