OpenAI GPT OSS 120B inference overview

Price per 1M tokens

$0.15 (input)
$0.60 (output)

Parameters

5.1B (active)
117B (total)

Context Window

131K

Release Date

Aug 2025

OpenAI GPT OSS 120B inference details

OpenAI 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. The model supports configurable reasoning depth, full chain-of-thought access, and structured output generation. Instantly access GPT OSS 120B at some of the industry’s lowest token costs, all running on CoreWeave’s purpose-built AI cloud. Rapidly evaluate, monitor, and iterate on your agentic AI applications using integrated W&B Weave tracing, available readily through W&B Inference.

Created by: 

OpenAI

License: 

Apache 2.0

Model card: 

				
					import openai
import weave

# Weave autopatches OpenAI to log LLM calls to W&B
weave.init("<team>/<project>")

client = openai.OpenAI(
    # The custom base URL points to W&B Inference
    base_url='https://api.inference.wandb.ai/v1',

    # Get your API key from https://wandb.ai/authorize
    # Consider setting it in the environment as OPENAI_API_KEY instead for safety
    api_key="<your-apikey>",

    # Team and project are required for usage tracking
    project="<team>/<project>",
)

response = client.chat.completions.create(
    model="openai/gpt-oss-120b",
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Tell me a joke."}
    ],
)

print(response.choices[0].message.content)
				
			

OpenAI GPT OSS 120B resources

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Course
AI engineering course: Agents
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Guide
W&B Inference powered by CoreWeave
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Whitepaper
A primer on building successful AI agents