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GPT-5.1-Codex

OpenAI · Reasoning · 400K context · released Nov 13, 2025 · checked 6h ago

Ways to buy 2

Way to buyIn / out per 1M
OpenAI API
The lab's own API · cached $0.13
$1.25 / $10List price
Azure AI Foundry
Default region · cached $0.13
$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

GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows.

Takes text, image in and returns text. First listed Nov 14, 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.

Price history

$1$3$102026Nov 14, 2025Output $10Input $1.25

List price since Nov 14, 2025, from Internet Archive snapshots of the OpenRouter catalog, then daily reads.

SeenModelChange
Jul 28, 2026GPT-5.1-CodexCached input $0.125 to $0.13+4%
Jul 17, 2026GPT-5.1-CodexCached input $0.13 to $0.125-4%
May 29, 2026GPT-5.1-CodexCached input $0.125 to $0.13+4%

Questions

How much does GPT-5.1-Codex cost?

$1.25 per million input tokens and $10 per million output tokens, with cached input at $0.13.

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

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

Where is GPT-5.1-Codex cheapest?

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

Sources: OpenRouter's public model catalog and each provider's own pricing page, read every morning at 05:00 UTC; gateway fees re-read every Monday. List prices: your contract may differ. Logos via logo.dev; trademarks belong to their owners.

Price changes by email

Thursdays, only in weeks when an LLM API list price changed.

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