GPT-5.1 Codex API
About
Build advanced reasoning agents with GPT-5.1 Codex, a specialized AI model optimized for complex logic and chain-of-thought tasks. This model delivers cost-effective pricing at $1.25/1M input and $10.00/1M output tokens, native tool calling support. Access GPT-5.1 Codex via the Cloudflare AI Gateway API with up to 128K output tokens.
Capabilities
Input Modalities
textimage
Output Modalities
text
Reasoning
Yes
Structured Output
Limits
Context Window
400K
Tokens
Input Limit
400K
Tokens
Max Output
128K
Tokens
Pricing
Standard (per 1M tokens)
Input
$1.25
Output
$10.00
Caching (per 1M tokens)
Read
$0.13
Frequently Asked Questions
GPT-5.1 Codex by Cloudflare AI Gateway costs $1.25 per 1M input tokens and $10.00 per 1M output tokens. Cached reads cost $0.13 per 1M tokens.
Model Details
ID
openai/gpt-5.1-codex
Provider
Cloudflare AI GatewayFamily
gpt-codex
Release Date
Nov 13, 2025
Knowledge Cutoff
Sep 30, 2024
API Integration
NPM Package
ai-gateway-provider
Environment Variables
CLOUDFLARE_API_TOKEN
CLOUDFLARE_ACCOUNT_ID
CLOUDFLARE_GATEWAY_ID
API Base URL
https://gateway.ai.cloudflare.com/v1/${CLOUDFLARE_ACCOUNT_ID}/${CLOUDFLARE_GATEWAY_ID}/compat/