What’s the difference between proprietary, open weight, and open source AI?

# Understanding Three Types of AI Models When you use ChatGPT or Claude, you're using proprietary AI—models owned by big tech companies that keep their inner workings secret and charge you to access them through the internet, but these tend to be the most powerful options available. Open weight and open source models work differently: their underlying code or both code and training data are publicly available, making them cheaper and more transparent, though often less capable than proprietary versions. Choosing between them comes down to whether you prioritize performance and convenience (proprietary), or cost and transparency (open weight or open source).