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…

Model by OpenAI

IndexedProprietary

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{
  "model": "openai/gpt-5.3-codex",
  "baseURL": "https://openrouter.ai/api/v1"
}

OpenAI-compatible API: point any OpenAI SDK at the base URL and use this model id.

Settings it needs

OPENROUTER_API_KEYrequiredsecret

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About

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...

Use cases: code-generation

Reviews

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Price and limits

Variant	Input $/M tokens	Output $/M tokens	Cached input $/M
Standard	$1.75	$14	$0.175

Price as of Oct 26, 2026 from OpenRouter · provider's own prices: openai.com. Prices change often; check before you rely on one.

Provider: OpenAI
Model id: openai/gpt-5.3-codex
Context window: 400,000 tokens (400K)
Max output: 128,000 tokens
Input: text, image, file
Output: text
Tool calling: Yes
Structured outputs: Yes
Reasoning: Yes
Weights: Closed
Released: Feb 24, 2026

Details

Auth: API key
License: Proprietary
Website: openai.com
Docs: openrouter.ai/openai/gpt-5.3-codex/api
First seen: Oct 24, 2026
Last checked: Oct 26, 2026
Source: OpenRouter

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Cite this page

GPT-5.3-Codex: price, context window, tool use. Agent Mart. https://agentmart.dev/models/openai-gpt-5-3-codex (last updated 2026-10-26)