GPT-OSS 120B vs GPT-OSS 20B

1. Most powerful open-weight model

• 117B parameters (5.1B active) while fitting on a single H100 GPU.
• High reasoning quality compared to other open models.

2. Apache 2.0 license

• Fully permissive, no copyleft or patent restrictions.
• Safe for commercial products, research, and redistribution.

3. Configurable reasoning effort

• Supports adjustable reasoning: low, medium, high.
• Lets developers balance latency vs. depth.

4. Full chain-of-thought access

• Unlike closed commercial models, this exposes complete reasoning traces.
• Useful for debugging, auditing, safety research, and transparency.

5. Fine-tunable

• Fully supports parameter fine-tuning.
• Can be adapted to domain-specific workflows and proprietary datasets.

6. Agentic capabilities

• Built-in function calling.
• Native support for web browsing, Python execution, and structured outputs.
• Ideal for open-source agents, full-stack automation, and developer tooling.

7. Tooling ecosystem support

• Compatible with Chat Completions, Responses API, Assistants, Realtime, Batch, and Fine-tuning endpoints.
• Supports Image Generation, Code Interpreter (via Python runtime), and more.

8. Open-source availability

• Downloadable on HuggingFace for local or on-prem deployment.
• Supports full offline, private, or self-hosted usage.

9. Streaming + function calling support

• Real-time interactions.
• Strong for interactive agents, coding assistants, and UI-driven workflows.

• Open-weight / Apache 2.0 licensed: you can use, modify, and deploy freely (commercially & academically) under permissive terms.
• Large model size (≈ 21B parameters) with Mixture-of-Experts (MoE) architecture: only ~3.6B parameters active per token, yielding efficient inference.
• Very long context window support: up to ~128 K tokens (or ~131 K tokens per some sources) enabling in-depth reasoning, long documents, or multi-turn context.
• Adjustable reasoning effort: you can trade latency vs quality by tuning “reasoning effort” levels.
• Efficient hardware requirements (for its class): designed to run on a single 16 GB-class GPU or optimized local deployments for lower latency applications.
• Strong for tasks such as reasoning, tool-use, structured output, chain-of-thought debugging: because the model is open and you can inspect its chain of thought.
• Flexibility: since weights are available, you can self-host, fine-tune, or deploy offline, giving more control than closed API models.