OpenAI

GPT-5.3 Codex

OpenAI's latest coding-focused model. Currently available in ChatGPT, API access coming soon.

flagship

Input price

$2/1M

Output price

$16/1M

Context window

200K

Max output

65.536K

Capabilities

textvisiontool-usecodereasoning

Benchmarks

MMLU-Pro90%

HumanEval96.5%

GPQA78%

Strengths

✓Best coding model from OpenAI
✓Large output window (65K tokens)
✓Strong reasoning for complex tasks

Weaknesses

✗API access not yet available
✗Premium pricing

Compare with similar models

GPT-5.3 Codex vs Claude Opus 4.6 GPT-5.3 Codex vs GPT-5.2 Codex GPT-5.3 Codex vs GPT-5 GPT-5.3 Codex vs Gemini 3.1 Pro GPT-5.3 Codex vs Gemini 3 Pro GPT-5.3 Codex vs Grok 4 GPT-5.3 Codex vs GLM-5 GPT-5.3 Codex vs Mistral Large 3