OpenAI released gpt-oss-120b and gpt-oss-20b, open-weight reasoning models, under the Apache 2.0 license. They were the company's first open-weight language models since GPT-2 in 2019. gpt-oss-120b runs on a single 80GB GPU and gpt-oss-20b on edge devices with 16GB of memory, with the model weights downloadable from Hugging Face. Both are Mixture-of-Experts (MoE) models: gpt-oss-120b holds 116.8 billion parameters in total but runs only 5.1 billion of them for any given token, which is what lets it fit on one GPU. The release drew attention as a shift for OpenAI, which had long pursued a closed-model strategy.