Last refreshed 2026-06-29. Next refresh: weekly.
Why use GPT-5.1 Codex Max on Vercel AI Gateway?
Vercel AI Gateway offers GPT-5.1 Codex Max with pay-as-you-go pricing at $1.25/1M input tokens. Vercel AI Gateway is a unified AI proxy providing a single OpenAI-compatible API endpoint to 275+ models from 25+ providers including Anthropic, OpenAI, Google, Meta, Mistral, DeepSeek, xAI, Alibaba, Amazon, ByteDance, Cohere, MiniMax, MoonshotAI, KwaiPilot, Black Forest Labs, Recraft, Voyage AI, NVIDIA, and more.
Compare GPT-5.1 Codex Max across 3 providers to find the best fit for your use caseSetup recipe
Python + curlpip install openaiexport AI_GATEWAY_API_KEY=...import os
from openai import OpenAI
client = OpenAI(
api_key=os.environ["AI_GATEWAY_API_KEY"],openai/gpt-5.1-codex-maxRequest example
import os
from openai import OpenAI
client = OpenAI(
api_key=os.environ["AI_GATEWAY_API_KEY"],
base_url="https://ai-gateway.vercel.sh/v1"
)
response = client.chat.completions.create(
model="openai/gpt-5.1-codex-max",
messages=[{"role": "user", "content": "Hello"}]
)
print(response.choices[0].message.content)Gotchas
- Use provider model ID "openai/gpt-5.1-codex-max", not the LLMReference slug "gpt-5.1-codex-max".
- creator/model-name e.g. kwaipilot/kat-coder-pro-v2
- The examples expect AI_GATEWAY_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 |
| Query | $10.00 |
Capabilities
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.