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GPT OSS 120B

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GPT OSS 120B is OpenAI's open-source 120-billion parameter language model, offering strong general-purpose capability with the transparency and flexibility of open weights.

ReasoningTool Use
index.ts
import { streamText } from 'ai'


const result = streamText({
  model: 'openai/gpt-oss-120b',
  prompt: 'Why is the sky blue?'
})

What To Consider When Choosing a Provider

  • Configuration: GPT OSS 120B ships with open weights, so you can inspect the model, understand its behavior, and deploy it in environments where model transparency is required.
  • Configuration: At 120B parameters, this is a substantial model. Through AI Gateway you access it as a managed API without handling infrastructure.
  • Zero Data Retention: AI Gateway supports Zero Data Retention for this model via direct gateway requests (BYOK is not included). To configure this, check the documentation.
  • Authentication: AI Gateway authenticates requests using an API key or OIDC token. You do not need to manage provider credentials directly.

When to Use GPT OSS 120B

Best For

  • Transparency-required deployments: Applications where model weights must be inspectable or auditable
  • Research and experimentation: Teams studying large language model behavior with full access to architecture
  • Open-source strategy: Organizations committed to open-source AI infrastructure
  • General-purpose tasks: Chat, content generation, analysis, and coding at a capable model scale

Consider Alternatives When

  • Maximum proprietary capability: GPT-5 or GPT-5.2 for higher closed-source capability
  • Smaller open-source: Gpt-oss-20b for lighter-weight open-source deployments
  • Cost optimization: Smaller models for tasks that don't require 120B parameter scale
  • Specialized tasks: Codex models for coding, o-series for reasoning

Conclusion

GPT OSS 120B combines substantial language model capability with the openness of public weights. Available through AI Gateway as a managed API, it serves teams that need both capable AI and model transparency.

Frequently Asked Questions

  • What does 'open-source' mean for GPT OSS 120B?

    The model weights are publicly available. You can inspect and audit the model while using it through managed APIs.

  • How does GPT OSS 120B compare to GPT-5?

    GPT-5 is OpenAI's closed-source general-purpose model with higher capability. GPT OSS 120B offers strong general-purpose performance with the advantage of open weights and model transparency.

  • What context window does GPT OSS 120B support?

    131.1K tokens, providing substantial capacity for document processing and extended conversations.

  • How does AI Gateway handle authentication for GPT OSS 120B?

    AI Gateway accepts a single API key or OIDC token for all requests. You don't embed OpenAI credentials in your application; AI Gateway routes and authenticates on your behalf.

  • What are typical latency characteristics?

    This page shows live throughput and time-to-first-token metrics measured across real AI Gateway traffic.