GPT-OSS-120B

About GPT-OSS-120B

GPT-OSS-120B is a groundbreaking open-weight language model from OpenAI, designed to bring state-of-the-art AI reasoning capabilities to everyone. With a massive 117 billion parameters, it's a powerhouse for complex problem-solving, creative tasks, and advanced analysis. What makes it truly special is its Mixture-of-Experts (MoE) architecture, which smartly activates only about 5.1 billion parameters per token. This clever design makes it surprisingly efficient to run, capable of operating on a single high-end 80GB GPU. Released under the fully permissive Apache 2.0 license, it grants unparalleled freedom for commercial use, modification, and distribution. Whether you're an AI researcher pushing the boundaries of machine intelligence, a developer building the next generation of AI applications, or a business looking to integrate powerful reasoning into your products, GPT-OSS-120B offers a perfect blend of top-tier performance, operational efficiency, and open-source accessibility. It's more than just a model; it's a versatile tool for innovation.

Features of GPT-OSS-120B

Mixture-of-Experts (MoE) Architecture

This is the secret sauce behind the model's efficiency. GPT-OSS-120B has 128 expert networks within its 36 layers, but for each piece of information it processes, it only consults 4 of them. This means you get the reasoning power of a colossal 117B-parameter model, but it runs using the computational resources closer to a much smaller model. It's like having a team of 128 specialists, but only calling in the exact four experts needed for each specific task, saving immense time and energy.

Advanced Chain-of-Thought Reasoning

The model doesn't just jump to answers; it shows its work. GPT-OSS-120B has built-in Chain-of-Thought (CoT) capabilities, allowing it to break down complex questions into logical steps. You can even configure the reasoning intensity (low, medium, high) to suit your needs, whether you want a quick answer or a detailed, step-by-step derivation. This makes it exceptionally strong in areas like mathematics, coding, and scientific reasoning, providing transparent and trustworthy outputs.

Extended 128K Context Window

With the ability to handle up to 128,000 tokens of context, GPT-OSS-120B can work with extremely long documents, maintain coherence throughout lengthy multi-turn conversations, and analyze large codebases. This vast context window allows it to understand nuanced narratives, reference information from much earlier in a conversation, and provide highly relevant and consistent responses for complex, long-form tasks.

Flexible Tool Integration & Open License

GPT-OSS-120B is built for real-world applications with native support for tool use, including web browsing and Python code execution. This allows it to interact with external data and perform actions. Crucially, its Apache 2.0 license removes all barriers for developers and companies. You can freely use, modify, and distribute the model for any purpose, including commercial products, without restrictive fees or usage limits, fostering true innovation.

Use Cases of GPT-OSS-120B

AI Research and Development

Researchers can use GPT-OSS-120B as a powerful baseline or component for experimenting with novel AI techniques, studying reasoning in large models, and advancing the field of machine learning. Its open-weight nature allows for deep inspection, fine-tuning, and modification, making it an invaluable resource for academic labs and R&D teams pushing the frontiers of what's possible with AI.

Building Commercial AI Applications

Startups and enterprises can integrate GPT-OSS-120B directly into their software products and services. From creating intelligent customer support agents and sophisticated content generation platforms to developing complex data analysis tools, the permissive license allows for commercial deployment without licensing worries, providing a cost-effective way to leverage cutting-edge AI.

Complex Code Generation and Analysis

Developers can harness the model's strong reasoning for tasks like generating entire code modules from natural language descriptions, debugging complex software, explaining legacy code, or converting code between programming languages. Its long context window is perfect for understanding large codebases and providing relevant, context-aware programming assistance.

Educational Tutoring and Content Creation

The model's step-by-step reasoning capability makes it an excellent tool for creating interactive learning experiences. It can tutor students in STEM subjects by working through problems, generate detailed educational content like textbooks or study guides, and help creators draft long-form articles, scripts, or technical documentation with high coherence and depth.

Frequently Asked Questions

What hardware do I need to run GPT-OSS-120B?

Thanks to its efficient MoE architecture and MXFP4 quantization, you can run a performant version of GPT-OSS-120B on a single GPU with 80GB of VRAM, such as an NVIDIA H100 or A100. For CPU-only or lower-memory inference, you may need to use more aggressive quantization methods or leverage cloud-based GPU instances that meet these memory requirements.

How does GPT-OSS-120B's performance compare to other models?

Independent benchmarks show that GPT-OSS-120B achieves near-parity with models like o4-mini on core reasoning tasks and excels in specific areas like HealthBench and competition math. It is recognized as a top-tier open-weight model for intelligence, offering an excellent balance of reasoning capability and computational efficiency compared to other large models.

What frameworks support GPT-OSS-120B?

The model is highly compatible and can be run using popular inference frameworks. This includes Hugging Face Transformers for easy integration, vLLM for high-throughput serving, Ollama for simple local deployment, and LM Studio for a user-friendly desktop interface. This flexibility lets you choose the best tool for your deployment scenario.

Can I fine-tune GPT-OSS-120B for my specific task?

Yes, absolutely! One of the major advantages of its open-weight Apache 2.0 license is that you have full access to the model weights. This means you can fine-tune GPT-OSS-120B on your proprietary dataset to specialize its knowledge for your unique domain, whether that's legal documents, medical literature, or your company's internal data, creating a tailored AI assistant.