Last refreshed 2026-06-04. Next refresh: weekly.
Why use GPT-5.1 Codex Max on OpenAI API?
OpenAI API offers GPT-5.1 Codex Max with pay-as-you-go pricing at $1.25/1M input tokens. OpenAI is a leading AI research and deployment company dedicated to developing safe and beneficial artificial general intelligence (AGI) for humanity.
Compare GPT-5.1 Codex Max across 3 providers to find the best fit for your use caseInput / 1M
$1.25
Output / 1M
$10.00
Cache
read $0.125
Batch
Not sourced
Setup recipe
Python + curlInstall
pip install openaiAuth
export OPENAI_API_KEY=...Call
import os
from openai import OpenAI
client = OpenAI() # reads OPENAI_API_KEY from env
response = client.chat.completions.create(Model ID
gpt-5.1-codex-maxRequest example
import os
from openai import OpenAI
client = OpenAI() # reads OPENAI_API_KEY from env
response = client.chat.completions.create(
model="gpt-5.1-codex-max",
messages=[{"role": "user", "content": "Hello"}]
)
print(response.choices[0].message.content)Gotchas
- Use the model slug directly, e.g. "gpt-4o" or "gpt-4.1-mini".
- The examples expect OPENAI_API_KEY; rename it only if your application config maps the new variable.
Compare GPT-5.1 Codex Max Across Providers
| Provider | Input (per 1M) | Output (per 1M) |
|---|---|---|
| Vercel AI Gateway | $1.25 | $10.00 |
| OpenRouter | $1.25 | $10.00 |
| OpenAI API | $1.25 | $10.00 |
Pricing
| Type | Price (per 1M) |
|---|---|
| Input tokens | $1.25 |
| Output tokens | $10.00 |
Capabilities
VisionMultimodalReasoningJSON / Tool useStructured Outputs
About GPT-5.1 Codex Max
OpenAI's GPT-5.1-Codex-Max is a code-specialized model released November 19, 2025, optimized for agentic coding tasks including project-scale refactors, debugging, and multi-file edits. Uses context compaction to handle long-running tasks beyond a single context window. 30% more token-efficient than previous Codex on SWE-bench. Supports an extra-high reasoning effort option.
Get Started
Model Specs
Released2025-11-19
Knowledge cutoff2024-09