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.
import { streamText } from 'ai'
const result = streamText({ model: 'openai/gpt-5.1-instant', prompt: 'Why is the sky blue?'})Playground
Try out GPT-5.1 Instant by OpenAI. Usage is billed to your team at API rates. Free users (those who haven't made a payment) get $5 of credits every 30 days.
Providers
Route requests across multiple providers. Copy a provider slug to set your preference. Visit the docs for more info. Using a provider means you agree to their terms, listed under Legal.
P50 throughput on live AI Gateway traffic, in tokens per second (TPS). Visit the docs for more info.
P50 time to first token (TTFT) on live AI Gateway traffic, in milliseconds. View the docs for more info.
Direct request success rate on AI Gateway and per-provider. Visit the docs for more info.
More models by OpenAI
| Model |
|---|
| 1M | 0.6s | 88tps | $5.00/M | $30.00/M | Read: $0.5/M Write: — | $10.00/K + input costs | — |   | 04/24/2026 | ||||
| 400K | 1.4s | 280tps | $0.75/M | $4.50/M | Read:$0.07/M Write:— | $10.00/K + input costs | — | | 03/17/2026 | ||||
| 400K | 0.6s | 148tps | $0.20/M | $1.25/M | Read:$0.02/M Write:— | $10.00/K + input costs | — | | 03/17/2026 | ||||
| 1.1M | 0.6s | 63tps | $2.50/M | $15.00/M | Read: $0.25/M Write: — | $10.00/K + input costs | — | | 03/05/2026 | ||||
| 400K | 3.3s | 157tps | $0.25/M | $2.00/M | Read:$0.03/M Write:— | $14/K + input costs | — | | 08/07/2025 | ||||
| 131K | 0.1s | 2404tps | $0.35/M | $0.75/M | Read:$0.25/M Write:— | — | — |    +5 | 08/05/2025 |
About GPT-5.1 Instant
GPT-5.1 Instant was released on November 12, 2025 as part of the GPT-5.1 model generation on AI Gateway. It's optimized for speed across general-purpose tasks, targeting applications where response latency is the binding constraint.
The model brings GPT-5.1 generation improvements to a speed-first profile. It handles chat, content generation, summarization, analysis, and other general-purpose tasks at latencies designed for real-time interaction. The context window of 128K tokens supports substantial input lengths even in speed-optimized mode.
If you're building real-time products, GPT-5.1 Instant eliminates the tradeoff between model generation quality and response speed. It shows what the GPT-5.1 architecture can deliver when optimized primarily for throughput and latency rather than maximum reasoning depth.
What To Consider When Choosing a Provider
- Configuration: GPT-5.1 Instant is tuned for the fastest possible responses within the GPT-5.1 family. It's the right choice when time-to-first-token and total response time matter most.
- Configuration: Unlike the codex variants which specialize in coding, instant handles any general-purpose task, from chat to content generation to analysis.
- 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-5.1 Instant
Best For
- Real-time chat interfaces: Consumer-facing products where response speed directly affects user experience
- Streaming applications: Live content generation, real-time translation, and interactive features
- High-throughput APIs: Backend services that need fast inference for many concurrent requests
- Interactive search: Augmented search experiences that generate instant responses
- Preprocessing pipelines: Fast classification and routing before handing off to specialized models
Consider Alternatives When
- Maximum quality: GPT-5.1 thinking for tasks where reasoning depth matters more than speed
- Coding tasks: GPT-5.1 codex family for software engineering workflows
- Extended reasoning: O3 or o4-mini for problems requiring chain-of-thought deliberation
- Absolute minimum cost: GPT-5 nano if the task is simple enough for a smaller model
Conclusion
GPT-5.1 Instant is the speed-optimized choice in the GPT-5.1 family, built for applications where fast responses and high throughput are the priority. Available through AI Gateway, it brings GPT-5.1 generation quality to real-time workloads.
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.