GPT OSS 120B is OpenAI's open-source 120-billion parameter language model, offering strong general-purpose capability with the transparency and flexibility of open weights.
import { streamText } from 'ai'
const result = streamText({ model: 'openai/gpt-oss-120b', prompt: 'Why is the sky blue?'})GPT OSS 120B became available on August 5, 2025 on AI Gateway as part of OpenAI's open-source model initiative. At 120 billion parameters, it is the larger of the two initial open-source releases, providing strong general-purpose language model capability with the transparency of open weights.
Open weights mean the model's parameters are publicly available, enabling inspection, auditing, and customization that closed-source models don't permit. For organizations with requirements around model transparency or regulatory compliance, this is significant.
Through AI Gateway, teams can use GPT OSS 120B as a managed API without handling the infrastructure required to serve a 120B parameter model.