openai

GPT 5.3 Codex (Fast)

Input / 1M: $3.675
Output / 1M: $29.4
Context: 400,000 tokens
Catalog: Gateway catalog

About this model

GPT-5.3-Codex advances both the frontier coding performance of GPT‑5.2-Codex and the reasoning and professional knowledge capabilities of GPT‑5.2, together in one model, which is also 25% faster. This enables it to take on long-running tasks that involve research, tool use, and complex execution.

text inputimage inputtext outputlanguage

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Thinking guide →

1const response = await fetch('https://api.minirouter.sh/v1/chat/completions', {2  method: 'POST',3  headers: {4    Authorization: `Bearer ${process.env.MINIROUTER_KEY}`,5    'Content-Type': 'application/json',6  },7  body: JSON.stringify({8    model: 'openai/gpt-5.3-codex-fast',9    messages: [{ role: 'user', content: 'Why is the sky blue?' }],10    max_tokens: 1024,11  }),12})13 14const data = await response.json()15console.log(data.choices[0].message.content)

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Overview

Model type: language
Context window: 400,000
Maximum output: 128,000
Input / 1M tokens: $3.675
Output / 1M tokens: $29.4
Released: 2026-02-05

Prices include the MiniRouter fee. Compatibility snapshot: 2026-08-06. Input: text, image. Output: text.

Endpoints

/v1/chat/completions/v1/messages/v1/responses

Platform-funded routing only. Caller BYOK credentials and OIDC-based upstream authentication are intentionally excluded; authenticate with a MiniRouter bearer key.

Captured parameters: max_tokens, temperature, stop, tools, tool_choice, reasoning, include_reasoning, response_format, structured_outputs.

Structured output: JSON Schema and JSON mode enforced on verified providers. How it works

API

Use the setup panel above to switch between Chat Completions, Messages, and client configurations. Every snippet keeps the model ID unchanged.

Base URLhttps://api.minirouter.sh/v1

Model IDopenai/gpt-5.3-codex-fast

Providers

MiniRouter selects from the configured routes below. Priority is the catalog order, not a latency or availability score.

Provider	Priority	Input / 1M	Output / 1M	Parameters	Access
vercel	1	$3.675	$29.4	max_tokens, temperature, stop, tools, tool_choice, reasoning, include_reasoning, response_format, structured_outputs	MiniRouter balance