OpenAI · MultimodalReleased 2026-02-24

gpt-5.3-codex

openai/gpt-5.3-codex id

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.

ReasoningTool useChatWeb searchCodeFill-in-the-middle

Type

Use gpt-5.3-codex

# Drop-in OpenAI-compatible client
$ import { generateText } from 'ai'
$ 
$ const { text } = await generateText({
$   model: 'openai/gpt-5.3-codex',
$   baseURL: 'https://synapse.garden/api/v1',
$   apiKey: process.env.MG_KEY,
$   prompt: 'Why is the sky blue?',
$ })

400K

CONTEXT WINDOW

128K

MAX OUTPUT

$1.93/M

INPUT · PER M

$15.40/M

OUTPUT · PER M

PRICING

List prices, every modality.

Rate	Per million tokens · USD
Input	$1.93/M
Output	$15.40/M
Cache read	$0.193/M

Honest list pricesHow we calculate prices

Other OpenAI models

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Model

Input

Output

Context

Type

FAQ · GPT-5.3-CODEX

Frequently asked

01 / 04

How do I call gpt-5.3-codex from my code?

Use the OpenAI or Anthropic SDK and point baseURL at https://synapse.garden/api/v1. Set model: ‘openai/gpt-5.3-codex’ and supply your Synapse Garden API key. No code changes beyond the base URL.

02 / 04

How much does gpt-5.3-codex cost?

Input: $1.93/M per million tokens. Output: $15.40/M per million tokens. The free tier includes a million tokens every month at no cost.

03 / 04

What's the context window for gpt-5.3-codex?

gpt-5.3-codex supports a context window of 400K tokens, with a maximum output of 128K tokens.

04 / 04

Do I need a separate Anthropic or OpenAI account?

No. Synapse Garden is the single API surface — one key gives you OpenAI, Anthropic, Google, Meta, Mistral, DeepSeek, xAI, Cohere, and more. Billing, rate limits, and audit logs are unified.

READY

Try gpt-5.3-codex in three minutes.

Sign up, create a key, drop our base URL into your existing client. The free tier includes a million tokens every month — no credit card.

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