# GPT OSS 120B

A 120-billion parameter open-source model from OpenAI, providing strong general-purpose language capability with open weights for transparency and customization.

- **Model ID:** `openai/gpt-oss-120b`
- **Type:** chat
- **Providers:** baseten, bedrock, fireworks, groq, parasail, nebius, togetherai, cerebras
- **Context window:** 131,072
- **Maximum output tokens:** 131,072
- **Pricing:** $0.35/1M input tokens, $0.75/1M output tokens
- **Canonical page:** https://vercel.com/ai-gateway/models/gpt-oss-120b

## Supported parameters

Detailed capability metadata has not been reported for this model.

## Example

```ts
import { streamText } from 'ai'

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

## About

GPT OSS 120B became available on August 5, 2025 on AI Gateway as part of OpenAI's open-source model initiative. At 120 billion parameters, it is the larger of the two initial open-source releases, providing strong general-purpose language model capability with the transparency of open weights.

Open weights mean the model's parameters are publicly available, enabling inspection, auditing, and customization that closed-source models don't permit. For organizations with requirements around model transparency or regulatory compliance, this is significant.

Through AI Gateway, teams can use GPT OSS 120B as a managed API without handling the infrastructure required to serve a 120B parameter model.

## What to consider

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.

At 120B parameters, this is a substantial model. Through AI Gateway you access it as a managed API without handling infrastructure.

## When to use

### 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

## 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

- **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

## 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.

## Links

- [Model page](https://vercel.com/ai-gateway/models/gpt-oss-120b)
- [AI Gateway documentation](https://vercel.com/docs/ai-gateway)
- [Provider model documentation](https://www.baseten.co/library/gpt-oss-120b/)
- [Provider pricing](https://inference-docs.cerebras.ai/support/pricing)