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The Open-Source Revolution is Here

Today marks a historic moment: OpenAI has released GPT-OSS-120B and GPT-OSS-20B, their first open-weight models since GPT-2 in 2019. We’re bringing you the most powerful one: GPT-OSS-120B, now live on Chat-O as a Balanced tier model.

What Makes GPT-OSS-120B Special?

This isn’t your typical open-source model. GPT-OSS-120B delivers state-of-the-art performance with real advantages:

  • Exceptional Reasoning: Matches or exceeds o4-mini on core benchmarks
  • Strong Tool Use: Built for agentic workflows with excellent instruction following
  • Efficient Architecture: 117B total parameters, but only activates 5.1B per token
  • Flexible Licensing: Apache 2.0 license for complete freedom

Real Performance Numbers

GPT-OSS-120B doesn’t just talk the talk—it delivers results:

  • Outperforms o3-mini on competition coding and general problem solving
  • Matches o4-mini on reasoning benchmarks like MMLU and Codeforces
  • Exceeds o4-mini on health-related queries and competition mathematics
  • Chain-of-thought reasoning with adjustable effort levels

Chat-O: Where New Models Launch First

While others are still reading the announcement, you’re already chatting with GPT-OSS-120B. This is exactly why we built Chat-O—instant access to breakthrough AI the moment it’s released.

The Chat-O Advantage:

  • ✅ Same-day availability for major releases
  • ✅ Multi-model conversations (compare GPT-OSS-120B with Claude, Gemini, or Grok)
  • ✅ No setup required—just select and start chatting

Perfect for Developers and Thinkers

GPT-OSS-120B excels at complex tasks that matter:

  • Advanced Coding: Strong performance on competitive programming challenges
  • Mathematical Reasoning: Transparent step-by-step problem solving
  • Research & Analysis: Clear chain-of-thought explanations
  • Tool Integration: Built for agentic workflows and function calling

Try It Now

Ready to experience OpenAI’s most powerful open-weight model? Jump into Chat-O and start a conversation with GPT-OSS-120B right now.

New to Chat-O? Create your free account and get 1,000 credits to explore GPT-OSS-120B alongside our full lineup of cutting-edge models.

Why This Matters

Transparency Meets Power: Unlike proprietary models, GPT-OSS-120B is completely open-weight under Apache 2.0. You get enterprise-grade performance with full transparency.

Multi-Model Magic: Compare insights from GPT-OSS-120B, Claude 3.7, and Gemini 2.5 in one conversation. See how different reasoning approaches tackle your problems.

We’re Just Getting Started

GPT-OSS-120B is live now, but this is just the beginning. Our team continuously monitors AI releases worldwide, ensuring Chat-O users get first access to every breakthrough model.

Ready to think bigger? Start your Chat-O journey today and discover what’s possible when you have the world’s most advanced AI models—including the brand-new GPT-OSS-120B—at your fingertips.

The future of AI is open, powerful, and available right now on Chat-O.