ChatGPT is not open source — OpenAI keeps the underlying model code private

ChatGPT runs on a proprietary model that OpenAI does not release to the public. You can use ChatGPT through OpenAI's website or app, but you cannot see, modify, or run the underlying code yourself. This is different from open source software, where the source code is published so anyone can inspect it, change it, and redistribute it.

OpenAI has released some related tools with more openness — like the GPT-4 API, which lets developers build applications on top of ChatGPT — but the core model itself remains closed. If you want to use a large language model that is actually open source, you have other options, though they work differently than ChatGPT.

Key Takeaways

  • ChatGPT's underlying model is proprietary, meaning you cannot see or modify the code that powers it.
  • OpenAI does offer an API so developers can build applications using ChatGPT, but this is not the same as open source.
  • Open source language models like Llama 2, Mistral, and Falcon exist and can be run on your own computer, though they may perform differently than ChatGPT.
  • The choice between proprietary and open source models depends on what you need: convenience and performance versus control and transparency.

What "open source" actually means in this context

Open source means the source code — the human-readable instructions that make a program work — is publicly available for anyone to read, modify, and redistribute. For a language model, this means you can see how it was trained, what data it learned from, and how it generates responses. You can also run it on your own computer without relying on a company's servers.

Proprietary software, by contrast, keeps the source code secret. You use it through an interface (like ChatGPT's website), but you never see or touch the underlying code. OpenAI decides what features to add, what safety rules to enforce, and when to shut down access. You have no way to modify the model's behavior beyond the options OpenAI provides.

Why OpenAI keeps ChatGPT proprietary

OpenAI's reasoning centers on safety, control, and business model. A proprietary model lets OpenAI enforce consistent safety guardrails — rules designed to prevent the model from generating harmful content. If the code were public, anyone could remove those safeguards or use the model in ways OpenAI did not intend.

There is also a financial incentive. OpenAI invested billions in training ChatGPT and runs expensive servers to power it. Keeping the model proprietary lets OpenAI charge for access through subscriptions and API fees. An open source model would be free to use, which would not fund continued development.

OpenAI has published research papers describing how ChatGPT works at a high level, but not the actual code or the full training data. This gives researchers insight without giving competitors or bad actors a complete blueprint.

Open source language models you can use instead

Several open source language models exist and are genuinely free to download and run. Llama 2, released by Meta, is one of the most capable. Mistral 7B, made by Mistral AI, is smaller and faster. Falcon, developed by the Technology Innovation Institute, is another option. All three have their source code and weights (the numerical parameters that make the model work) publicly available.

The trade-off is that these models are generally less powerful than ChatGPT. They may give less accurate answers, struggle with complex reasoning, or produce lower-quality text. They also require more technical knowledge to set up — you need to download the model files, install software like Ollama or LM Studio, and run it on your own computer or server. You are not paying OpenAI, but you are paying in setup time and computing power.

If you want an open source model with a web interface similar to ChatGPT, you can use services like Hugging Face, which hosts open source models and lets you chat with them in a browser. The experience is closer to ChatGPT, but the underlying model is still less capable.

The difference between open source models and the ChatGPT API

OpenAI offers a ChatGPT API that developers can use to build applications. This is not open source — you still cannot see the code — but it does give you some control. You can send text to OpenAI's servers, get a response, and integrate it into your own software. You pay per request, not a flat subscription.

The API is useful if you want to build a custom application on top of ChatGPT without running the model yourself. But you are still dependent on OpenAI: if OpenAI changes the API, raises prices, or shuts down access, your application breaks. With an open source model, you own the code and can modify it however you want.

Transparency and safety concerns with proprietary models

Because ChatGPT is proprietary, you cannot independently verify how it works or what data it was trained on. OpenAI publishes a technical report, but researchers cannot audit the full training process or test the model's behavior in ways OpenAI did not anticipate. This is a genuine limitation if transparency matters to you.

Open source models solve this problem — anyone can inspect the code and training data. However, open source does not automatically mean safer. An open source model can still be trained on biased data or produce harmful outputs. The difference is that with open source, the community can identify and fix these problems, whereas with proprietary models, you have to trust the company to do so.

Licenses and what you can legally do with each

ChatGPT's terms of service restrict how you can use it. You cannot use ChatGPT to train another AI model, and you cannot use it to compete with OpenAI. OpenAI retains ownership of the model and can change the terms at any time.

Open source models come with licenses that spell out what you can do. Llama 2 uses the Llama 2 Community License, which lets you use it for research and commercial purposes but has some restrictions on competing with Meta. Mistral 7B uses the Apache 2.0 license, which is more permissive. Falcon uses the Apache 2.0 license as well. If you plan to build a commercial product, check the specific license to make sure it allows what you want to do.

Frequently Asked Questions

Can I download ChatGPT and run it on my own computer?

No. ChatGPT only runs on OpenAI's servers. You access it through a web browser or mobile app, but you cannot download the model itself. If you want to run a language model locally, you need to use an open source model like Llama 2 or Mistral.

If I use the ChatGPT API, do I own the code I write?

You own the code you write, but not the underlying model. OpenAI owns ChatGPT. You can use the API to build applications, but you cannot modify ChatGPT itself or claim ownership of the model.

Are open source language models as good as ChatGPT?

Not yet. ChatGPT generally produces better answers, especially for complex tasks. Open source models are improving rapidly, but most are still behind ChatGPT in capability. The gap depends on the specific task — some open source models are competitive for simple questions.

What if I want ChatGPT but with more control?

Your best option is the ChatGPT API, which lets you build custom applications. You still cannot modify the model itself, but you can control how it is used and what data flows through it. For full control, you would need to switch to an open source model.

Is there a middle ground between proprietary and fully open source?

Some companies release models with restricted licenses — available to researchers or non-commercial users but not for commercial competition. Llama 2 is an example. These offer more openness than ChatGPT but more control than fully permissive licenses.