GPT 5.1 Thinking
GPT 5.1 Thinking is the reasoning-focused member of the GPT-5.1 family, applying extended chain-of-thought computation to produce more thorough and accurate responses on complex analytical, scientific, and multi-step problems.
import { streamText } from 'ai'
const result = streamText({ model: 'openai/gpt-5.1-thinking', prompt: 'Why is the sky blue?'})What To Consider When Choosing a Provider
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.
GPT 5.1 Thinking generates internal reasoning tokens before producing its final response, similar to the o-series reasoning models but within the GPT-5.1 architecture. This produces better results on hard problems at the cost of longer response times.
Use GPT 5.1 Thinking for your hardest queries and GPT-5.1 instant for everything else. A routing layer can direct traffic based on query complexity.
When to Use GPT 5.1 Thinking
Best For
Complex analysis:
Multi-step research, data analysis, and strategic reasoning that benefits from deliberation
Mathematical problem solving:
Proofs, derivations, and quantitative analysis requiring verified steps
Scientific reasoning:
Physics, chemistry, and biology problems with multi-step logical chains
Hard coding problems:
Algorithm design, optimization, and architectural decisions requiring extended thought
Extended chain-of-thought:
The GPT-5.1 generation's deliberation tier, complementing the speed-optimized instant variant
Consider Alternatives When
Fast responses needed:
GPT-5.1 instant for real-time interactions
Coding agent workflows:
GPT-5.1 codex family for autonomous software engineering
Pure STEM reasoning:
The o-series reasoning models for the deepest chain-of-thought capability in OpenAI's lineup
General chat:
GPT-5.1 instant for conversational workloads where reasoning depth is unnecessary
Conclusion
GPT 5.1 Thinking brings extended reasoning to the GPT-5.1 family, producing more thorough and accurate results on complex problems. For analytical, scientific, and multi-step tasks routed through AI Gateway, it is the depth-focused counterpart to the speed-optimized instant variant.
FAQ
It generates internal reasoning tokens that work through the problem step by step before producing a visible response, similar to the approach used in o-series reasoning models.
Use thinking for complex analysis, math, science, and hard coding problems where accuracy is the priority. Use instant for real-time chat, streaming content, and tasks where speed is the priority.
Yes. The extended reasoning process adds time before the first visible output. The tradeoff is deeper, more accurate reasoning on complex problems.
400K tokens, supporting the lengthy inputs that complex reasoning tasks often require.
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.
This page shows live throughput and time-to-first-token metrics measured across real AI Gateway traffic.
