Last refreshed 2026-05-11. Next refresh: weekly.
Why use GPT-5.1 Codex Max on OpenRouter?
OpenRouter offers GPT-5.1 Codex Max with pay-as-you-go pricing at $1.25/1M input tokens. 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.
Compare GPT-5.1 Codex Max across 2 providers to find the best fit for your use caseSetup recipe
Docs fallbackUse the provider REST API or SDKCreate a provider API keymodel: openai/gpt-5.1-codexopenai/gpt-5.1-codexRequest example
openai/gpt-5.1-codex.Gotchas
- Use provider model ID "openai/gpt-5.1-codex", not the LLMReference slug "gpt-5.1-codex-max".
Compare GPT-5.1 Codex Max Across Providers
| Provider | Input (per 1M) | Output (per 1M) |
|---|---|---|
| OpenRouter | $1.25 | $10.00 |
| Vercel AI Gateway | $1.25 | $10.00 |
Pricing
| Type | Price (per 1M) |
|---|---|
| Input tokens | $1.25 |
| Output tokens | $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.
FAQ
What does GPT-5.1 Codex Max cost on OpenRouter?
On OpenRouter, GPT-5.1 Codex Max costs $1.25 per 1M input tokens and $10 per 1M output tokens.
What is the context window for GPT-5.1 Codex Max on OpenRouter?
GPT-5.1 Codex Max supports a 400k token context window on OpenRouter.
How does OpenRouter compare to other GPT-5.1 Codex Max providers?
GPT-5.1 Codex Max is available from 2 providers. The cheapest input pricing is $1.25/1M tokens from OpenRouter.
What API model ID do I use for GPT-5.1 Codex Max on OpenRouter?
Use the model ID openai/gpt-5.1-codex when calling OpenRouter's API.
Who created GPT-5.1 Codex Max?
GPT-5.1 Codex Max was created by OpenAI as part of the GPT-5.1 model family.
Is GPT-5.1 Codex Max open source?
GPT-5.1 Codex Max is not open source; the seed data lists it as proprietary.