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OpenAI: GPT-5.1-Codex-Max

openai/gpt-5.1-codex-max
Dec 4, 2025400K context128K max output$1.25/M in · $10.00/M outReasoning

Description

GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks. It is based on an updated version of the 5.1 reasoning stack and trained on agentic workflows spanning software engineering, mathematics, and research. GPT-5.1-Codex-Max delivers faster performance, improved reasoning, and higher token efficiency across the development lifecycle.

Specifications

Provider
openai
Context Length
400K
Max Output
128K
Modality
Intextimage
Outtext

Pricing

TypePrice / 1M tokens
Input$1.25
Output$10.00
Cache Read$0.13
Web Search$0.01 / call

Quick Start

curl https://api.ominigate.ai/v1/chat/completions \
  -H "Authorization: Bearer sk-omg-your-api-key" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "openai/gpt-5.1-codex-max",
    "messages": [{"role": "user", "content": "Hello!"}]
  }'
OpenAI: GPT-5.1-Codex-Max — Pricing & API on OminiGate