GPT-5.3-Codex

Approved Data Classifications

This model is only approved for Open Data. When leveraging NaviGator AI’s suite offerings, please ensure you are selecting models that meet the compliance requirements in accordance with UF’s Data Classifications, grant awards or project specifications, and state and federal law.

Description

GPT-5.3-Codex is OpenAI's coding-optimized model for long-horizon, agentic software tasks. It is an upgraded version of GPT-5.3 for Codex and similar coding environments, supports reasoning.effort settings (low, medium, high, and xhigh), and accepts text and image input with text output. The model provides a 400,000-token context window with up to 128,000 output tokens and a Sep 30, 2025 knowledge cutoff. Pricing is $2.20 per 1M input tokens, $17.60 per 1M output tokens, and $0.22 per 1M cached input tokens.

Capabilities

Model	Knowledge Cutoff	Input	Output	Context Length	Cost (per 1 million tokens)
gpt-5.3-codex	Aug 31 2025	Text, Image, Pdf	Text	400,000	$1.75/1M input $14.00/1M output

info

• 1M represents 1 Million Tokens
• All prices listed are based on 1 Million Tokens
• Cached input: $0.22 per 1M tokens

Availability

Cloud Provider

Usage

curl

curl -X POST https://api.ai.it.ufl.edu/v1/chat/completions \
-H "Content-Type: application/json" \
-H "Authorization: Bearer <API_TOKEN>" \
-d '{
    "model": "gpt-5.3-codex",
    "messages": [
        {
            "role": "system",
            "content": "You are a helpful assistant."
        },
        {
            "role": "user",
            "content": "Write a haiku about an Alligator."
        }
    ]
}'

python

from openai import OpenAI

client = OpenAI(
    api_key="your_api_key",
    base_url="https://api.ai.it.ufl.edu/v1"
)

response = client.chat.completions.create(
    model="gpt-5.3-codex", # model to send to the proxy
    messages = [
        { "role": "system", "content": "You are a helpful assistant." },
        {
            "role": "user",
            "content": "Write a haiku about an Alligator."
        }
    ]
)

print(response.choices[0].message)

javascript

import OpenAI from 'openai';

const openai = new OpenAI({
  apiKey: 'your_api_key',
  baseURL: 'https://api.ai.it.ufl.edu/v1'
});

const completion = await openai.chat.completions.create({
    model: "gpt-5.3-codex",
    messages: [
        { role: "system", content: "You are a helpful assistant." },
        {
            role: "user",
            content: "Write a haiku about an Alligator.",
        },
    ],
});

console.log(completion.choices[0].message)

---

References

1. OpenAI GPT-5.3-Codex Model
   https://platform.openai.com/docs/models/gpt-5.3-codex
2. OpenAI API Pricing
   https://openai.com/api/pricing/