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GPT-5.1-Codex-Max

OpenAI · Reasoning · 400K context · released Dec 4, 2025 · checked 10h ago

Ways to buy 2

Way to buyIn / out per 1M
OpenAI API
The lab's own API · cached $0.125
$1.25 / $10List price
Azure AI Foundry
Default region · cached $0.125
$1.25 / $10Same as list

USD per 1M tokens. Regions are separate routes.

Through a gateway

Your own numbers

100M input and 20M output tokens a month: $325.00 direct.

No published token fee: Martian Gateway, Portkey, TrueFoundry AI Gateway.

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About GPT-5.1-Codex-Max

GPT-5.1-Codex-Max is OpenAI’s latest agentic coding model, designed for long-running, high-context software development tasks.

Takes text, image in and returns text. First listed Dec 6, 2025. Up to 128K output tokens. Blended price $3.44 per 1M tokens at 3 input to 1 output. Model id gpt-5-1-codex-max.

Price history

$1$3$102026Dec 6, 2025Output $10Input $1.25

List price since Dec 6, 2025, from Internet Archive snapshots of the OpenRouter catalog, then daily reads.

Questions

How much does GPT-5.1-Codex-Max cost?

$1.25 per million input tokens and $10 per million output tokens, with cached input at $0.125.

What is the context window of GPT-5.1-Codex-Max?

400K tokens, with up to 128K tokens of output.

Where is GPT-5.1-Codex-Max cheapest?

Of 2 routes tracked, Azure AI Foundry is cheapest at $1.25 input and $10 output per million tokens.

List prices from providers' pages on the date shown; your contract may differ. Logos via logo.dev; trademarks belong to their owners.

Weekly: LLM API list prices that changed, Thursday mornings.