gpt-oss-120b is an open-weight, 117B-parameter Mixture-of-Experts (MoE) language model from OpenAI designed for high-reasoning, agentic, and general-purpose production use cases. It activates 5.1B parameters per forward pass and is optimized to run on a single H100 GPU with native MXFP4 quantization. The model supports configurable reasoning depth, full chain-of-thought access, and native tool use, including function calling, browsing, and structured output generation.
Modalities
Price
Free
Context
131K
Released
Aug 5, 2025
Knowledge Cutoff
Jun 2024
Token volume and request traffic to this model over time.
gpt-oss-120b is an open-weight, 117B-parameter Mixture-of-Experts (MoE) language model from OpenAI designed for high-reasoning, agentic, and general-purpose production use cases. It activates 5.1B parameters per forward pass and is optimized to run on a single H100 GPU with native MXFP4 quantization.
Yes. The pricing shown on this page for gpt-oss-120b is zero, so you are not charged for prompt or completion tokens. Free endpoints are rate limited — see the rate limit docs.
gpt-oss-120b has a 131,072 token context window.
GPT-5.6 Luna Pro, GPT-5.6 Luna, GPT-5.6 Terra Pro and 55 more are other text models from OpenAI.
gpt-oss-120b was released on August 5, 2025. Its knowledge cutoff is June 30, 2024.