OpenAI API exposes GPT-5.1 Codex through model ID gpt-5.1-codex. Use the setup steps, sourced pricing, capabilities, and official provider links below to validate this route before deployment.
Last refreshed 2026-04-27. Next refresh: weekly.
Quick Start
- 1
- 2Use the OpenAI API SDK or REST API to call
gpt-5.1-codex— see the documentation for request format. - 3
Code Examples
Install
pip install openaiAPI key
OPENAI_API_KEYModel ID
gpt-5.1-codexUse the model slug directly, e.g. "gpt-4o" or "gpt-4.1-mini".
import os
from openai import OpenAI
client = OpenAI() # reads OPENAI_API_KEY from env
response = client.chat.completions.create(
model="gpt-5.1-codex",
messages=[{"role": "user", "content": "Hello"}]
)
print(response.choices[0].message.content)Pricing on OpenAI API
| Type | Price (per 1M) |
|---|---|
| Input tokens | $1.25 |
| Output tokens | $10.00 |
Capabilities
VisionMultimodalJSON / Tool useStructured OutputsCode Execution
About GPT-5.1 Codex
GPT-5.1-Codex is a coding-specialized version of GPT-5.1, optimized for software engineering and agentic coding workflows at 400K context.
Model Specs
Released2025-12-01
Context400k
ArchitectureDecoder Only
Knowledge cutoff2024-09