GPT OSS
UnclaimedOpen-weight reasoning models from OpenAI for agentic and developer tasks
What is GPT OSS?
GPT OSS is a series of open-weight language models by OpenAI designed for reasoning, agentic tasks, and developer use cases. The models come in two sizes: gpt-oss-120b (117B parameters with 5.1B active) for production workloads on 80GB GPUs, and gpt-oss-20b (21B parameters with 3.6B active) for lower latency and local deployment. Both use the harmony response format and support function calling, web browsing, Python code execution, and structured outputs with configurable reasoning effort.
Key Features of GPT OSS
- Permissive Apache 2.0 license
- Configurable reasoning effort (low, medium, high)
- Full chain-of-thought access
- Fine-tunable for specific use cases
- Native agentic capabilities (function calling, web browsing, Python execution)
- MXFP4 quantization support
- Harmony response format
- Structured Outputs support
Who Should Use GPT OSS?
Production general-purpose reasoning tasks
Local or specialized deployments
Agentic system development
Code generation and execution
Web browsing integration
Custom model fine-tuning
Low-latency inference applications
GPT OSS: Pros & Cons
✓Pros
- Permissive Apache 2.0 license enabling commercial deployment
- Full transparency with complete chain-of-thought reasoning access
- Efficient MXFP4 quantization for running on single 80GB GPU
- Two model sizes for different latency/capability trade-offs
- Native function calling and tool use capabilities
- Fully customizable through fine-tuning
✕Cons
- Models require Harmony response format to function correctly
- Reference implementations (PyTorch, Triton, Metal) are educational and not recommended for production
- gpt-oss-120b requires 80GB GPU memory
- Higher reasoning effort increases latency
Tags
Tool Details
- Company
- OpenAI
- Pricing
- Free
- Category
- Ai Coding
- Added
- Jun 2026
- Last Updated
- Jun 2026
More Ai Coding Tools
7 tools in the same category
Test OpenAI's open-weight models in an interactive playground
Build full-stack mobile apps 10x faster with AI—from idea to App Store in minutes
One API. Access all top AI models. Build faster. Spend less.
Multi-session AI IDE with atomic branching for developers who ship fast
Want to list your AI tool on NextStair?
Submit Tool