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OpenAI

GPT-OSS 120B

Open GPT reasoning model for self-hosted agents and controllable deployments

Released
Aug 5 2025
Modality
Text
Context
125K tokens
Price in / cached input / out
$0.097 / $0.053 / $0.73per 1M tokens

Quickstart

OpenAI-compatible: change the base URL, and the setup is complete.

from openai import OpenAI
import os

client = OpenAI(
    base_url="https://api.you.com/v1",
    api_key=os.environ["YOU_API_KEY"],
)

response = client.chat.completions.create(
    model="gpt-oss-120b",
    messages=[{"role": "user", "content": "Summarize this support ticket in two sentences."}],
)

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

Specifications

Technical details, capabilities, pricing, and data handling.

Model info

Input Modality
Text
Output Modality
Text
Context Window
125K
Parameters
117B total / 5.1B active
License
Apache 2.0

Capabilities

Reasoning
Supported
Function calling
Supported
Structured outputs
Supported
Web search grounding
Not supported

Pricing

Input
$0.097
Cached input
$0.053
Output
$0.73

Data handling

Zero data retention
Supported
No training on customer data
Supported
Regions
US

Providers

Access models through multiple providers with automatic routing and built-in failover.

Providers serving GPT-OSS 120B
ProviderZDRNo trainingRegion
You InferenceYesYes
US
ParasailYesYes
US

When to use GPT-OSS 120B

Guidance based on the specifications and benchmarks on this page.

Best for

  • Low-cost reasoning at scaleOpenAI reports near-parity with o4-mini on core reasoning benchmarks while activating only 5.1B parameters per token.
  • Agentic tool use workflowsNative function calling, web browsing, Python execution, and Structured Outputs, with adjustable reasoning effort.
  • Self-hosting and fine-tuningApache 2.0 weights run on a single 80GB GPU and can be fine-tuned on a single H100 node.
Get API key

Consider alternatives for

  • You need image understandingGPT-OSS 120B is text-only, trained on a mostly English, text-only dataset.
  • You need over 128K contextThe model natively supports context lengths of up to 128K tokens.
  • You need top expert-level reasoningIt scores 19.0% on Humanity's Last Exam with tools, below OpenAI o3's 24.9% in the same release.

Benchmarks

GPT-OSS 120B results alongside comparable models

Reasoning benchmark scores
BenchmarkGPT-OSS 120BOpenAIDeepSeek V4 ProDeepSeekDeepSeek V4.1 FlashDeepSeekKimi K3Moonshot AIQwen3.8 MaxAlibabaGLM 5.3Z.ai
GPQA Diamond80.1%90.1%90.9%93.5%92.6%Not evaluated
Humanity's Last Exam14.9%37.7%36.8%43.5%43.6%Not evaluated
Humanity's Last Exam (with tools)19%48.2%63.9%56%56.2%62.5%
AIME 202592.5%Not evaluatedNot evaluatedNot evaluatedNot evaluatedNot evaluated

Scores are self-reported by each model’s developer, so settings may vary between models. Sources: GPT-OSS 120B (model card), DeepSeek V4 Pro (Hugging Face), DeepSeek V4.1 Flash (Hugging Face), Kimi K3 (Hugging Face), Qwen3.8 Max (Hugging Face), Qwen3.8 Max (release post), GLM 5.3 (Hugging Face).

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