GPT 5.1 Codex

Chat Completions

gpt-5.1-codex

OpenAI|Created Nov 13, 2025|400k context

Chat Completions

GPT-5.1-Codex is a specialized version of GPT-5.1 optimized for software engineering and coding workflows. It's 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, closely follows developer instructions, and produces cleaner, higher-quality code. Codex integrates into developer environments like the CLI, IDE extensions, GitHub, and cloud tasks. It adapts its reasoning dynamically—providing quick answers for small tasks and sustaining long, multi-hour runs for large projects. The model is trained for structured code reviews, identifying critical flaws by reasoning over dependencies and validating behavior against tests. It also supports multimodal inputs like images or screenshots for UI development and integrates tools for search, dependency installation, and environment setup. Codex is specifically intended for agentic coding applications.

Overview Specifications Activity Performance Uptime Examples

Pricing-50%

Pay-as-you-go rates for this model. More details can be found here.

Input Tokens (1M)

$0.63

Cached Input Tokens (1M)

$0.06

Output Tokens (1M)

$5.00

Capabilities

Input Modalities

TextImage

Output Modalities

Text

Supported Parameters

Available parameters for API requests

Frequency PenaltyFunction CallFunctionsLogit BiasMax Completion TokensParallel Tool CallsPredictionPresence PenaltyReasoning EffortResponse FormatStopTool ChoiceToolsWeb Search Options

Usage Analytics

Token usage of this model on our platform

Throughput

Not enough throughput data

Time-To-First-Token (TTFT)

Not enough TTFT data

Code Example

Example code for using this model through our API with Python (OpenAI SDK) or cURL. Replace placeholders with your API key and model ID.

Basic request example. Ensure API key permissions. For more details, see our documentation.

from openai import OpenAI

client = OpenAI(
    base_url="https://api.naga.ac/v1",
    api_key="YOUR_API_KEY",
)

resp = client.chat.completions.create(
    model="gpt-5.1-codex",
    messages=[
        {"role": "user", "content": "What's 2+2?"}
    ],
    temperature=0.2,
)
print(resp.choices[0].message.content)