GPT-OSS 120B vs o3
Compare pricing, context windows, and strengths for GPT-OSS 120B by OpenAI and o3 by OpenAI - and see how to put either to work in Appaca.
GPT-OSS 120B
OpenAI's most powerful open-weight model (117B params, 5.1B active), fitting on a single H100 GPU - fully customizable, licensed for unrestricted commercial use.
View GPT-OSS 120Bo3
A powerful reasoning model excelling at complex, multi-step tasks across math, science, coding, and visual reasoning; succeeded by GPT-5.
View o3GPT-OSS 120B vs o3 at a glance
Specs and pricing side by side, from the Appaca AI models directory.
| Spec | GPT-OSS 120B | o3 |
|---|---|---|
| Provider | OpenAI | OpenAI |
| Model type | Text | Text |
| Context window | 131.1K tokens | 200K tokens |
| Input price | Free (open weight) | $2 / 1M tokens |
| Output price | Free (open weight) | $8 / 1M tokens |
| Status | Current | Current |
How GPT-OSS 120B and o3 differ
What the numbers mean in practice when choosing between GPT-OSS 120B and o3.
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GPT-OSS 120B is an open-weight model with no per-token licensing fees, while o3 charges $2 per million input tokens.
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o3's 200K tokens context window is roughly 1.5x larger than GPT-OSS 120B's 131.1K tokens, so it can work across bigger codebases, contracts, or archives in one pass.
Strengths side by side
Where each model shines, according to benchmarks and provider positioning.
GPT-OSS 120B
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.
o3
1. Advanced reasoning capability
- Designed for multi-step thinking across text, code, and visual inputs.
- Excels at math, science, logic puzzles, and complex analytical workflows.
2. Strong performance across domains
- Highly capable in technical writing, data analysis, and structured problem-solving.
- Useful for research, engineering tasks, and intricate instruction-following.
3. Visual reasoning support
- Accepts image inputs, enabling tasks such as diagram analysis, chart interpretation, and visual logic assessments.
4. High output capacity
- Up to 100,000 output tokens, supporting long-form content, technical breakdowns, and multi-part solutions.
5. Excellent instruction following
- Produces detailed, step-by-step responses for tasks requiring precision and clarity.
- Ideal for educational explanations, system design reasoning, and code walkthroughs.
6. Large 200K context window
- Handles long documents, multi-file reasoning, or extended conversations with minimal loss of context.
7. Broad API support
- Works with Chat Completions, Responses, Realtime, Assistants, Batch, Embeddings, Image Generation, and more.
- Supports streaming and function calling for advanced workflows.
8. Positioned as a legacy reasoning model
- Remains extremely capable but formally succeeded by GPT-5, which offers stronger reasoning and performance.
Use GPT-OSS 120B or o3 - or both
Appaca is the AI workspace for operators. Build internal tools and AI co-workers powered by GPT-OSS 120B or o3 - connected to your real data and ready for your whole team. No code, no deployment.
Describe it, and it's built
Tell the Appaca agent the internal tool you need and it builds a working app powered by GPT-OSS 120B or o3. No code, no API keys, no deployment.
Switch models without rebuilding
Start on GPT-OSS 120B, test the same tool on o3, and keep whichever performs better - the rest of your app stays exactly as it is.
Automated for the whole team
Schedule tools to run on autopilot - daily digests, weekly reports, real-time triggers - and share them with your whole team from one workspace.
Describe it, and it's built
Tell the Appaca agent what your team needs and it builds a working app powered by GPT-OSS 120B or o3 - connected to the tools you already use.
Related comparisons
See how GPT-OSS 120B and o3 stack up against other models in the directory.
FAQs
GPT-OSS 120B is open weight and free of per-token licensing fees, while o3 costs $2 per million input tokens and $8 per million output tokens.
o3 has the larger context window at 200K tokens, compared to 131.1K tokens for GPT-OSS 120B. A larger window means the model can consider more text at once - useful for long contracts, codebases, or months of records.
It depends on the job. Compare the pricing, context window, and strengths above against your workload - and remember the choice isn't permanent. In Appaca you can build a tool on GPT-OSS 120B, test the same tool on o3, and switch at any time without rebuilding anything.
Yes. Appaca is a no-code AI workspace: describe the internal tool your team needs and the Appaca agent builds it as a working app powered by GPT-OSS 120B, o3, or any other model in the directory - with a built-in database, team access, and integrations. No API keys to wire up and nothing to deploy.
Build AI tools with GPT-OSS 120B or o3
Describe the tool your team needs and get a working app powered by the model you choose - with a built-in database, team access, and integrations. No code, no deployment.