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OpenAI: GPT-5.3-Codex

GPT-5.3-Codex is OpenAI’s most advanced agentic coding model, combining the frontier software engineering performance of GPT-5.2-Codex with the broader reasoning and professional knowledge capabilities of GPT-5.2. It achieves state-of-the-art results...

#51 Code Mode‡$1.75/1M input tokens†
‡Kilo Code Leaderboard†OpenRouter
Context Window
400,000 tokens
Max Output
128,000 tokens
Input Modalities
textimagefile

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Benchmarking OpenAI: GPT-5.3-Codex

Real-World Usage

Real-world usage statistics from the Kilo Code community

Weekly Token Usage

Mode Rankings (Last Week)

Where this model ranks for each built-in mode

Code

Write, modify, and refactor code

#51

Ask

Get answers and explanations

#63

Debug

Diagnose and fix software issues

#39

Orchestrator

Coordinate tasks across multiple modes

#37

Real-world metrics from the Kilo Code Leaderboard

Pricing

Cost per 1 million tokens

Input Tokens
$1.75
per 1M tokens
Output Tokens
$14.00
per 1M tokens

Example Cost

Analyzing a 10,000 line codebase (≈40k input tokens, 10k output tokens) costs approximately $0.2100

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-5.3-codex
Created
February 24, 2026
Tokenizer
GPT
Input Modalities
text, image, file
Context Window
400,000 tokens
Max Completion Tokens
128,000 tokens
Input Price
$1.75 per 1M tokens
Output Price
$14.00 per 1M tokens
Cache Read Price
$0.17 per 1M tokens
Content Moderation
Enabled

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