---
title: GPT-OSS-120B Free — Reasoning LLM | ModelsLab
description: Run OpenAI's free gpt-oss-120b locally. Powerful reasoning model with o4-mini performance on single GPU. Download now.
url: https://modelslab-frontend-v2-927501783998.us-east4.run.app/openai-gpt-oss-120b-free
canonical: https://modelslab-frontend-v2-927501783998.us-east4.run.app/openai-gpt-oss-120b-free
type: website
component: Seo/ModelPage
generated_at: 2026-05-13T10:37:06.887350Z
---

Available now on ModelsLab · Language Model

OpenAI: Gpt-oss-120b (free)
Reasoning. Local. Free.
---

[Try OpenAI: Gpt-oss-120b (free)](/models/open_router/openai-gpt-oss-120b-free) [API Documentation](https://docs.modelslab.com)

Deploy Enterprise Reasoning Locally
---

Near-Parity Performance

### O4-Mini Level Reasoning

Matches OpenAI o4-mini on core benchmarks while running on single 80GB GPU.

Apache 2.0 Licensed

### Build Without Restrictions

Commercial-grade freedom. No copyleft, no patent risk, full customization support.

Mixture-of-Experts

### 128 Experts, 4 Active

Efficient routing activates specialized experts per token for optimized inference.

Examples

See what OpenAI: Gpt-oss-120b (free) can create
---

Copy any prompt below and try it yourself in the [playground](/models/open_router/openai-gpt-oss-120b-free).

Code Generation

“Write a production-grade Python function that implements a binary search tree with insert, delete, and search operations. Include comprehensive error handling and type hints.”

Mathematical Reasoning

“Solve this step-by-step: A rectangular garden is 24 meters long and 18 meters wide. If you want to build a path of uniform width around the perimeter, and the path area equals the garden area, what is the path width?”

Technical Documentation

“Create API documentation for a REST endpoint that accepts user authentication tokens and returns paginated results. Include request/response schemas, error codes, and rate limiting details.”

Data Analysis

“Analyze quarterly sales data trends across three regions and identify which product categories show growth potential. Recommend optimization strategies based on patterns.”

For Developers

A few lines of code.
Reasoning model. Zero cost.
---

ModelsLab handles the infrastructure: fast inference, auto-scaling, and a developer-friendly API. No GPU management needed.

- **Serverless:** scales to zero, scales to millions
- **Pay per token,** no minimums
- **Python and JavaScript SDKs,** plus REST API

[API Documentation ](https://docs.modelslab.com)

PythonJavaScriptcURL

Copy

```
<code>import requests

response = requests.post(
    "https://modelslab.com/api/v7/llm/chat/completions",
    json={
  "key": "YOUR_API_KEY",
  "prompt": "",
  "model_id": ""
}
)
print(response.json())</code>
```

FAQ

Common questions about OpenAI: Gpt-oss-120b (free)
---

[Read the docs ](https://docs.modelslab.com)

### What makes gpt-oss-120b free compared to other OpenAI models?

GPT-OSS-120B is released as open-weight under Apache 2.0 license, allowing free download and local deployment without API costs. You run it on your own hardware instead of cloud infrastructure.

### Can I run gpt-oss-120b on my local machine?

Yes. The model requires an 80GB GPU like H100 for full deployment, or you can use the lighter gpt-oss-20b variant on 16GB consumer hardware. Both support local inference via Ollama, LM Studio, or HuggingFace.

### How does gpt-oss-120b compare to o4-mini performance?

GPT-OSS-120B achieves near-parity with o4-mini on core reasoning benchmarks including coding, competition math, and tool use. It delivers comparable results at zero API cost when self-hosted.

### What is the context window and output limit?

GPT-OSS-120B supports 131,072 token context window and 131,072 max output tokens, enabling long-document processing and extended reasoning chains.

### Does gpt-oss-120b support fine-tuning?

Yes. Full-parameter fine-tuning is supported, allowing you to adapt the model for domain-specific or task-specific applications without retraining from scratch.

### What reasoning effort levels are available?

Three configurable levels—low, medium, and high—let you trade latency for performance. Set reasoning effort in your system message for each request.

Ready to create?
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Start generating with OpenAI: Gpt-oss-120b (free) on ModelsLab.

[Try OpenAI: Gpt-oss-120b (free)](/models/open_router/openai-gpt-oss-120b-free) [API Documentation](https://docs.modelslab.com)

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*This markdown version is optimized for AI agents and LLMs.*

**Links:**
- [Website](https://modelslab.com)
- [API Documentation](https://docs.modelslab.com)
- [Blog](https://modelslab.com/blog)

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*Generated by ModelsLab - 2026-05-13*