OpenAI: GPT-5 Codex

by OpenAI

GPT-5-Codex is a specialized version of GPT-5 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, debugg...

*Artificial Analysis‡Kilo Code Leaderboard†OpenRouter
Release Date
September 23, 2025
Context Window
400,000 tokens
Max Output
128,000 tokens
Input Modalities
textimage

Coding Performance

Coding benchmarks and performance metrics for development tasks

Coding Benchmarks

Artificial Analysis Coding Index

53.5%

Overall coding capability score

LiveCodeBench

84.0%

Real-world coding task performance

SciCode

40.9%

Scientific computing & algorithms

TerminalBench Hard

35.5%

CLI & terminal command generation

LCR (Long Context Reasoning)

69.0%

Understanding large codebases

IFBench

74.1%

Instruction following accuracy

0

Performance metrics from Artificial Analysis

Real-World Usage

Real-world usage statistics from the Kilo Code community

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Real-world metrics from the Kilo Code Leaderboard

Pricing

Cost per 1 million tokens

Input Tokens
$1.25
per 1M tokens
Output Tokens
$10.00
per 1M tokens
Blended (3:1 ratio)
$3.44
per 1M tokens

Example Cost

Analyzing a 10,000 line codebase (≈40k input tokens, 10k output tokens) costs approximately $0.1500

Coding Capabilities

Features and parameters relevant to coding tasks

Coding Features

Function Calling
Can call external functions/APIs
Tool Choice
Control over function selection
Structured Outputs
JSON schema validation
Reasoning Tokens
Extended thinking for complex problems

Pricing details from OpenRouter

Technical Details

Architecture and implementation specifications

Model ID
openai/gpt-5-codex
Created
September 23, 2025
Tokenizer
GPT
Input Modalities
text, image
Context Window
400,000 tokens
Max Completion Tokens
128,000 tokens
Input Price
$1.25 per 1M tokens
Output Price
$10.00 per 1M tokens
Cache Read Price
$0.13 per 1M tokens
Content Moderation
Enabled

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