Model detail
gpt-5.1
GPT-5.1 is the latest frontier-grade model in the GPT-5 series, offering stronger general-purpose reasoning, improved instruction adherence, and a more natural conversational style compared to GPT-5. It uses adaptive reasoning to allocate computation dynamically, responding quickly to simple queries while spending more depth on complex tasks. The model produces clearer, more grounded explanations with reduced jargon, making it easier to follow even on technical or multi-step problems. Built for broad task coverage, GPT-5.1 delivers consistent gains across math, coding, and structured analysis workloads, with more coherent long-form answers and improved tool-use reliability. It also features refined conversational alignment, enabling warmer, more intuitive responses without compromising precision. GPT-5.1 serves as the primary full-capability successor to GPT-5
Model specs
- Context length
- 400K
- Max output
- 128K
- I/O modalities
- Text / Image
- Released
- 2025-11
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API endpoints
One MixRoute gateway, OpenAI-compatible
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OpenAI-compatible
/v1/chat/completionsPOST
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Pricing
Flat rate, unit: /1M Tokens
Input
$1.2500 /1M Tokens
Completion
$10.0000 /1M Tokens
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Selection summary
Quickly judge whether it fits your workload
What is this model good for?
General reasoning, coding, and structured analysis
Use gpt-5.1 for broad tasks that need improved instruction adherence, clear explanations, and adaptive reasoning.
What should you check before using it?
Test conversational quality and task reliability
Evaluate multi-step reasoning, coding, tool use, and response style on representative prompts before changing default production routing.
How should you start?
Compare gpt-5.1 with your current GPT-5 baseline
Use model ID gpt-5.1 in the same client and evaluation harness as your current model, then promote it only after measured gains.
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Token cost estimator
Live estimate from this page's pricing, not an actual bill
This model has no cache-read price; caching is not counted
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FAQ
gpt-5.1 is intended for general reasoning, coding, structured analysis, and conversational tasks that benefit from strong instruction adherence and adaptive reasoning.
One endpoint, a testable decision
Test this model and alternate routes with the same request format
Start from a real workload, then let quality, total cost, and failure conditions decide whether to send production traffic.