These models are now accessible via AWS Bedrock and SageMaker, putting Amazon in direct play with Microsoft and giving AWS customers a new way to build and run AI applications using OpenAI technology.

Despite the company's name, OpenAI hasn't dropped an open version of its AI models since GPT-2 in 2019. That changed on Tuesday, as CEO Sam Altman shared two new open-weights, reasoning AI models, named gpt-oss-120b (120 billion parameters) and gpt-oss-20b (20 billion parameters).

We all know AI relies on open-source software, but most of the big AI companies avoid opening their code or their large language model (LLM) weights. Today, things have changed. OpenAI, the artificial intelligence titan behind ChatGPT,