How much does GPT-5.1-Codex cost?

GPT-5.1-Codex costs $1.25/M input tokens and $10.00/M output tokens, with separate rates for Cache Read at $0.13/M tokens.

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

GPT-5.1-Codex has a 400,000 token context window. It supports up to 128,000 completion tokens.

Does GPT-5.1-Codex support tool calling and structured outputs?

Yes. GPT-5.1-Codex accepts tools and tool_choice for function calling. It also supports structured outputs via a JSON schema in response_format.

What inputs and outputs does GPT-5.1-Codex support?

GPT-5.1-Codex accepts text and images as input and returns text.

Which providers serve GPT-5.1-Codex?

GPT-5.1-Codex is served by 1 provider on OpenRouter: Azure.

What other text models does OpenAI have?

GPT-6.1 Terra Pro, GPT-6.1 Terra, GPT-6 Luna Decisions and 58 more are other text models from OpenAI.

When was GPT-5.1-Codex released?

GPT-5.1-Codex was released on November 13, 2025.

OpenAI: GPT-5.1-Codex

openai/gpt-5.1-codex

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GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows. It is designed for both interactive development sessions and long, independent execution of complex engineering tasks. The model supports building projects from scratch, feature development, debugging, large-scale refactoring, and code review. Compared to GPT-5.1, Codex is more steerable, adheres closely to developer instructions, and produces cleaner, higher-quality code outputs. Reasoning effort can be adjusted with the reasoning.effort parameter. Read the docs here

Codex integrates into developer environments including the CLI, IDE extensions, GitHub, and cloud tasks. It adapts reasoning effort dynamically—providing fast responses for small tasks while sustaining extended multi-hour runs for large projects. The model is trained to perform structured code reviews, catching critical flaws by reasoning over dependencies and validating behavior against tests. It also supports multimodal inputs such as images or screenshots for UI development and integrates tool use for search, dependency installation, and environment setup. Codex is intended specifically for agentic coding applications.

Modalities

In / out price

$1.25 / $10per 1M

Context

400K

Released

Nov 13, 2025

Providers

This model is hosted by one provider. OpenRouter forwards every request without routing.

Latency / throughput


	$1.25	$10.00	$0.13	2.20s	63 tok/s	100.00%

Input $1.25Output $10.00
63 tok/s100.00% uptime

Pricing

The average price customers actually pay for this model, next to the prices providers post. Caching and discounts mean the price actually paid is often well below the listed one.

Weighted average

Input

$0.1862/M tokens

Output

$10/M tokens

GPT-5.1-Codex — Price history

Price history

No effective price data for this selection

		$0.186	$10.00	95.0%	100.0%

Effective in $0.186Effective out $10.00
Token share
100.0%

Uptime

Uptime is the percentage of the past 3 days that at least one provider was responding to requests. Availability is the percentage of time that inference was successfully served. OpenRouter continuously monitors and uses the next-best provider when one returns an error.

Uptime (3d)

100.00%

Availability (3d)

99.91%

Availability over the last 3 days

Last 72 hours

Availability 99.91%

3 Days Ago2 Days AgoYesterdayNow

Availability over the last 24 hours

OpenRouter Availability

99.87%

When an error occurs in an upstream provider, we can recover by routing to another healthy provider, if your request filters allow it. You can access per-provider uptime data programmatically through the Endpoints API. Learn more about our load balancing and provider routing options.

Benchmarks

Scores on standardized evaluations and this model’s own outputs on shared benchmark prompts. Higher percentages are better — and each rank shows where this model lands among the models evaluated on that source.

Benchmark score summary for OpenAI: GPT-5.1-Codex (Artificial Analysis, Design Arena and Vals AI)
Source	Benchmark	Score
Artificial Analysis	GPT-5.1 Codex (High) GPQA Diamond	86.0%
Artificial Analysis	GPT-5.1 Codex (High) HLE	25.7%
Artificial Analysis	GPT-5.1 Codex (High) IFBench	70.0%
Artificial Analysis	GPT-5.1 Codex (High) τ²-Bench Telecom	83.0%
Artificial Analysis	GPT-5.1 Codex (High) AA-LCR	69.3%
Artificial Analysis	GPT-5.1 Codex (High) CritPt	5.7%
Artificial Analysis	GPT-5.1 Codex (High) LiveCodeBench	84.9%
Artificial Analysis	GPT-5.1 Codex (High) Terminal-Bench Hard	34.8%
Artificial Analysis	GPT-5.1 Codex (High) MMLU-Pro	86.0%
Artificial Analysis	GPT-5.1 Codex (High) AIME 2025	95.7%
Design Arena	GPT-5.1 Codex Agents Arena Full Stack Elo	1086
Design Arena	GPT-5.1 Codex Agents Arena Mobile Apps Elo	1191
Design Arena	GPT-5.1 Codex Agents Arena Webapps Elo	995
Design Arena	GPT-5.1 Codex Models Arena Code Categories Elo	1142
Design Arena	GPT-5.1 Codex Models Arena Data Visualization Elo	1210
Design Arena	GPT-5.1 Codex Models Arena Game Development Elo	1127
Design Arena	GPT-5.1 Codex Models Arena UI Component Elo	1227
Design Arena	GPT-5.1 Codex Models Arena Website Elo	1154
Vals AI	GPT 5.1 Codex IOI v1	3.7%
Vals AI	GPT 5.1 Codex LiveCodeBench	85.5%
Vals AI	GPT 5.1 Codex Terminal-Bench 1.0	57.5%
Vals AI	GPT 5.1 Codex Vibe Code Bench v1.1	13.1%

Apps

Public apps that send the most traffic to this model. Good signal for what real production workloads look like — and a hint at which use cases this model is best suited for.

Hermes Agent

Hermes Agent is an open-source, self-improving AI agent by Nous Research that runs persistently with memory across sessions, and builds reusable skills from experience. It comes with 40+ built-in tools, including web search, browser automation, and vision, plus scheduled automations and subagents.

118Mtokens

Roo Code

Roo Code is a VS Code extension that gives you a team of specialized AI agents with customizable modes for coding, architecture, debugging, and review, all with flexibility across any LLM or model provider.

76.4Mtokens

DeepSeek Harness

new

61.4Mtokens

There are many coding agents, but this one is yours.

61Mtokens

Kilo Code

Kilo Code is an open-source AI coding agent that works across VS Code, JetBrains, and CLI to help developers ship code faster with agentic workflows.

59.3Mtokens

Rest of OpenRouter

81.8M

Top 5 Apps

23.1M

Not currently available through EU in-region routing. In-region routing docs

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OpenAI: GPT-5.1-Codex

Providers