GPT-5.3 Codex

Model details

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GPT-5.3 Codex

Model
gpt-5.3-codex
Provider
openai
API
openai-responses
Base URL
https://api.openai.com/v1
Input
text, image
Reasoning
Yes
Context window
400,000
Max tokens
128,000
Cost / million input
$1.75
Cost / million output
$14
Cost / million cache read
$0.175
Cost / million cache write
$0

Also available from other providers

Model config JSON
{
  "providers": {
    "openai": {
      "apiKey": "YOUR_API_KEY",
      "models": [
        {
          "id": "gpt-5.3-codex",
          "name": "GPT-5.3 Codex",
          "reasoning": true,
          "input": [
            "text",
            "image"
          ],
          "contextWindow": 400000,
          "maxTokens": 128000,
          "cost": {
            "input": 1.75,
            "output": 14,
            "cacheRead": 0.175,
            "cacheWrite": 0
          }
        }
      ],
      "api": "openai-responses",
      "baseUrl": "https://api.openai.com/v1"
    }
  }
}