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GPT-5.1 Instant

GPT-5.1 Instant is the fastest model in the GPT-5.1 family, optimized for low-latency responses across general-purpose tasks, delivering GPT-5.1 generation quality at speeds suited for real-time applications.

Tool UseVision (Image)File InputReasoningImplicit CachingWeb Search
index.ts
import { streamText } from 'ai'


const result = streamText({
  model: 'openai/gpt-5.1-instant',
  prompt: 'Why is the sky blue?'
})
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Frequently Asked Questions

  • How fast is GPT-5.1 Instant compared to other GPT-5.1 models?

    It is the fastest in the family, optimized for the lowest time-to-first-token and total response time at the cost of some reasoning depth compared to the thinking variant.

  • What tasks is GPT-5.1 Instant best suited for?

    Any general-purpose task where response speed matters: real-time chat, streaming content generation, interactive features, and high-throughput API services.

  • What context window does GPT-5.1 Instant support?

    128K tokens, providing substantial capacity even in speed-optimized mode.

  • How does GPT-5.1 Instant differ from GPT-5.1 thinking?

    Instant prioritizes speed; thinking prioritizes reasoning depth. Use instant for real-time interactions and thinking for problems that benefit from extended deliberation.

  • How does AI Gateway handle authentication for GPT-5.1 Instant?

    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.