gpt-oss-20b
Version: 2
Welcome to the gpt-oss series, OpenAI’s open-weight models designed for powerful reasoning, agentic tasks, and versatile developer use cases.
OpenAI is releasing two flavors of these open models:
gpt-oss-120b: A large open model designed to run in data centers and on high end desktops and laptops.
gpt-oss-20b: A medium-sized open model that can run on most desktops and laptops.
gpt-oss-20b: A medium-sized open model that can run on most desktops and laptops.
Highlights
- Permissive Apache 2.0 license: Build freely without copyleft restrictions or patent risk—ideal for experimentation, customization, and commercial deployment.
- Configurable reasoning effort: Easily adjust the reasoning effort (low, medium, high) based on your specific use case and latency needs.
- Full chain-of-thought: Gain complete access to the model’s reasoning process, facilitating easier debugging and increased trust in outputs. It’s not intended to be shown to end users.
- Fine-tunable: Fully customize models to your specific use case through parameter fine-tuning.
- Agentic capabilities: Use the models’ native capabilities for function calling, web browsing , Python code execution , and Structured Outputs.
- Native MXFP4 quantization: The models are trained with native MXFP4 precision for the MoE layer, making gpt-oss-120b run on a single H100 GPU and the gpt-oss-20b model run within 16GB of memory.
OpenAI Model Card
Please see OpenAI's gpt-oss-120b model card here.Model Specifications
Context Length131072
LicenseCustom
Last UpdatedAugust 2025
Input TypeText
Output TypeText
PublisherOpenAI
Languages1 Language