GPT-5.3-Codex — OpenAI | Modeldex

GPT-5.3-Codex

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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...

VisionLong context

API release

Feb 24, 2026(last month)

Not enough benchmark coverage yet for an Intelligence Index — needs at least 3 results across 2 categories.

Overview

History

GPT-5.3-Codex became available via the OpenAI API on 2026-02-24.

Training & availability

OpenAI has not released the underlying model weights — access is via their hosted API only.

Capabilities

Context window: 400K tokens.
Input modalities: text, image, file.

Recommended for: vision, long-context.

Pricing

Input: $1.7500 per 1M tokens
Output: $14.0000 per 1M tokens

Use the cost calculator above to estimate monthly spend for your workload.

Quick start

Minimal example using the openai API. Copy, paste, replace the key.

from openai import OpenAI

client = OpenAI(api_key="sk-...")
resp = client.chat.completions.create(
    model="gpt-5-3-codex",
    messages=[{"role": "user", "content": "Explain quantum computing in one sentence."}],
)
print(resp.choices[0].message.content)

Cost calculator

Estimate your monthly bill. Presets are typical workload sizes.

Input tokens / month5.0M

@ $1.75/1M

Output tokens / month2.0M

@ $14/1M

Input cost

$8.75

5.0M × $1.75/1M

Output cost

$28

2.0M × $14/1M

Total / month

$36.75

$441 / year

Integrations & tooling support

Tool calling: Not supported
Structured outputs: Not supported

Price vs quality

Not enough data

This model has no benchmark scores recorded yet.

Community ratings

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