GPT-5.1

by OpenAI

GPT-5.1 is a reasoning model in OpenAI's GPT-5 family, pairing advanced reasoning with vision and a 272,000-token context window. It targets complex reasoning tasks, coding, and professional work where the model can plan, weigh alternatives, and solve multi-step problems. It supports function calling, structured outputs, and vision input, which makes it a fit for agentic workflows, code analysis, and knowledge-intensive tasks across domains.

Key info

Input
Output
Features
Context window
272K
Max output
128K
Input price
$1.25 /1M
Output price
$10.00 /1M
  • EU residency available
  • US residency available
  • Zero data retention via Enterprise
  • No training by default
  • GDPR DPA available

Available routes

GPT-5.1 runs on 2 different routes through the Opper gateway. Compare residency, ZDR, and training posture at a glance β€” full data-handling detail per route below.

ProviderRegionZero data retentionTrainingInputOutput
AzureEUEnterpriseNo$1.25$10.00
OpenAIUSEnterpriseNo$1.25$10.00

Training posture across routes: No training on prompts by default.

Data handling per route

Each route hosting GPT-5.1 has its own privacy posture, residency, and GDPR terms. Postures are maintained by Opper with a last-verification timestamp.

Azure β€” SwedenπŸ‡ΈπŸ‡ͺ

Zero data retention is available via Opper Enterprise contract. No training on customer data. EU; DPA available.

Zero data retention
Available via Opper Enterprise contract.
Training
No training on customer data.
Logging
Abuse monitoring (30-day retention)
Third-party access
None disclosed
GDPR DPA
DPA available
Transfer mechanism
Not applicable β€” data stays in EU

OpenAI β€” United StatesπŸ‡ΊπŸ‡Έ

Zero data retention is available via Opper Enterprise contract. No training on customer data. US; SCCs; DPA available.

Zero data retention
Available via Opper Enterprise contract.
Training
No training on customer data.
Logging
Abuse monitoring (30-day retention)
Third-party access
None disclosed
GDPR DPA
DPA available
Transfer mechanism
SCCs

Benchmarks

Independent benchmark scores β€” composite indices for reasoning, coding, and math, plus individual eval scores where available.

Global rank#39 of 531 LLMs
TierStrong
Output speed106 tok/s
First token40.32s
Intelligence Index38.9
Coding Index44.7
Math Index94.0
Reasoning & knowledge
MMLU-Pro
87%
GPQA Diamond
87%
Humanity's Last Exam
27%
Long-context reasoning
75%
Coding
LiveCodeBench
87%
SciCode
43%
Agentic & tool use
Terminal-Bench Hard
45%
τ²-Bench Telecom
82%
Math & instruction following
AIME 2025
94%
IFBench
73%

Get started

Call GPT-5.1 through the Opper gateway with one API key. Let your coding agent set it up, or call it directly β€” Opper is drop-in compatible with the OpenAI, Anthropic, and Google AI SDKs.

Set it up with your agent

Copy this and paste it into your coding agent β€” Claude Code, Cursor, Codex, and more β€” and it'll wire up Opper for you.

Or call it directly

import OpenAI from "openai";
const client = new OpenAI({
apiKey: process.env.OPPER_API_KEY,
baseURL: "https://api.opper.ai/v3/compat",
});
const completion = await client.chat.completions.create({
model: "openai/gpt-5.1",
messages: [{ role: "user", content: "Hello" }],
});
console.log(completion.choices[0].message.content);

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Side-by-side on privacy, EU hosting, pricing, and benchmarks.

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GPT-5.1 by OpenAI β€” pricing, benchmarks, EU/US hosting | Opper AI