Using GPT-5.1 Codex Max on OpenRouter

Quick Start

1. 1
   Create an account at OpenRouter and generate an API key.
2. 2
   Use the OpenRouter SDK or REST API to call openai/gpt-5.1-codex — see the documentation for request format.
3. 3
   You'll be billed $1.25/1M input, $10.00/1M output tokens. See full pricing.

Code Examples

About OpenRouter

OpenRouter provides a unified interface for Large Language Models with better pricing, improved uptime, and no subscription requirements. Route across providers for cost optimization and reliability.

OpenRouter is a multi-provider LLM aggregator offering unified API access to 300+ models from all major labs and emerging providers, with automatic failover for reliability.

Pricing on OpenRouter

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.