OpenAI

GPT-5.1-Codex-Mini

GPT-5.1-Codex-Mini is a proprietary model from OpenAI, released Nov 13, 2025. It costs $0.25 per million input tokens and $2 per million output tokens, with a 400K-token context window.

Developer
OpenAI
Released
Nov 13, 2025
Context window
400K
Price in / out, per 1M tokens
$0.25 / $2
Weights
Proprietary
Inputs
Images, Text
Reasoning
Yes
Tool use
Yes

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WebDevLMArena1244138 / 1241.2K

LMArena, CC BY 4.0, as of Oct 22, 2026. Where a model is rated at several effort levels, its best is shown.

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OpenAI

The lab behind GPT and ChatGPT, which brought large language models to hundreds of millions of people. Founded 2015, based in San Francisco. openai.com

Questions

Who makes GPT-5.1-Codex-Mini?

GPT-5.1-Codex-Mini is made by OpenAI, founded 2015 and based in San Francisco.

How much does GPT-5.1-Codex-Mini cost?

$0.25 per million input tokens and $2 per million output tokens, at its provider’s list price.

What is GPT-5.1-Codex-Mini’s context window?

400K tokens (400,000).

Is GPT-5.1-Codex-Mini open source?

No. GPT-5.1-Codex-Mini is proprietary and served through its provider’s API.

Sources

Every number on this page comes from these sources; models without a published number show none. Download the data. Cite as “Nexus Explorer, nexus.inc/models”.