GPT 5.1

gpt-5.1 · OpenAI

GPT-5 is OpenAI’s most advanced language model, designed for complex tasks that require step-by-step reasoning, precise instruction following, and high reliability. It improves reasoning, code generation, and prompt understanding—including test-time routing and intent cues like “think hard about this”—while reducing hallucination and sycophancy.

API Pricing

Input$1.25 / 1M tokens
Output$10 / 1M tokens
Cache read$0.125 / 1M tokens

Specifications

Context400K tokens
Modalitiestext, image
Featuresthinking, web search, tool calling, deep search, function calling, structured outputs

Frequently asked questions

What is GPT 5.1?

GPT-5 is OpenAI’s most advanced language model, designed for complex tasks that require step-by-step reasoning, precise instruction following, and high reliability. It improves reasoning, code generation, and prompt understanding—including test-time routing and intent cues like “think hard about this”—while reducing hallucination and sycophancy.

What is the context length of GPT 5.1?

GPT 5.1 has a 400,000 token context window.

How much does GPT 5.1 cost?

On AIHubMix, GPT 5.1 costs $1.25 per million input tokens and $10 per million output tokens. Cached input reads are billed at $0.125 per million tokens.

What modalities does GPT 5.1 support?

GPT 5.1 accepts text and image input.

What capabilities does GPT 5.1 support?

GPT 5.1 supports thinking, web search, tool calling, deep search, function calling and structured outputs. Per-protocol parameter support is listed in the capability table on this page.

How do I call GPT 5.1 via API?

GPT 5.1 is available through the AIHubMix unified API. The API is OpenAI-compatible: point your OpenAI SDK at https://aihubmix.com/v1, use your AIHubMix API key, and set the model name to gpt-5.1 — no other code changes needed.

Who created GPT 5.1?

GPT 5.1 is developed by OpenAI. AIHubMix aggregates it alongside models from other providers behind one API and one bill.

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Use GPT 5.1 via the AIHubMix unified API — one interface for every major LLM.