I honestly didn’t think this day would come. OpenAI — the company that built its entire brand on keeping models locked behind APIs — just dropped [GPT-OSS](https://openai.com/index/introducing-gpt-oss/), their first open-weight large language model since GPT-2. And it’s not some watered-down afterthought. This thing is genuinely impressive.
Let’s talk numbers. GPT-OSS-120B packs 117 billion total parameters, but here’s the clever part: it uses a mixture-of-experts (MoE) architecture that only activates 5.1 billion parameters per token. Combined with MXFP4 quantization, the whole model fits on a single 80GB GPU like an NVIDIA H100. That’s wild for something that performs near the level of OpenAI’s own o4-mini on reasoning benchmarks. If you want something even lighter, they also released [gpt-oss-20b](https://huggingface.co/openai/gpt-oss-20b), which squeezes onto a 16GB card.
The license is Apache 2.0 — no weird restrictions, no usage caps, no “open but actually not” fine print. You can fine-tune it, deploy it commercially, or just tinker with it on your laptop during a long flight (someone on [Hacker News](https://news.ycombinator.com/item?id=45847733) literally reported running the 120B variant on a MacBook while traveling). The model excels at reasoning, tool use, and chain-of-thought tasks, outperforming o3-mini and even beating o4-mini on competition math and health-related queries.
The community response has been massive. The [GitHub repo](https://github.com/openai/gpt-oss) racked up nearly 20k stars quickly, [Hugging Face](https://huggingface.co/openai/gpt-oss-120b) already has the weights ready for download, and Hacker News threads are full of people sharing benchmarks and deployment setups — from [running it at 500 tokens/sec on Nvidia GPUs](https://news.ycombinator.com/item?id=44819968) to building RAG agents on top of it. It’s also available through Azure, Google Cloud Vertex AI, and OpenRouter if you’d rather not self-host.
Whether OpenAI did this because of competitive pressure from Meta’s Llama and DeepSeek, or because they genuinely want to support the open-source ecosystem, the result speaks for itself. GPT-OSS-120B is a strong model, it runs on accessible hardware, and the license actually lets you do things with it. That’s all most developers were ever asking for.
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