OpenAI: GPT-5.3 Codex

Name: GPT-5.3 Codex API
Brand: Openai

stable

GPT-5.3 Codex is available through Everstack's OpenAI-compatible gateway with routing, fallback, retries, and observability.

gpt-5.3-codexgpt-5released Feb 5, 2026

Provider Quick start

Context

400K

tokens

Max output

128K

tokens

Input

$1.75

per 1M

Output

$14.00

per 1M

Activity

Daily period usage

Aggregated managed Everstack traffic. Buckets below 5 tenants or 100 requests are withheld.

Providers

ProviderContextInput /MOutput /M

OpenAI

400K$1.75$14.00

Pricing

Item	Price	Unit
Input	$1.75	per 1M tokens
Output	$14.00	per 1M tokens
Cache read	$0.17	per 1M tokens

Performance

Reliability

Compare

Compare usage and performance

Place this model beside up to three other catalog models.

Capabilities

Modalities

Input

Output

Details

Model ID: gpt-5.3-codex
Family: gpt-5
Status: stable
Knowledge: -
Released: Feb 5, 2026

Gateway Config

API: 2024-01-01
Auth: OPENAI_API_KEY
Discovery: static
Provider type: static

Quick Start

index.ts

import Everstack from "@everstack/node";const client = new Everstack({  apiKey: process.env.EVERSTACK_API_KEY!,  baseUrl: "https://{instance}.{region}.everstack.ai",});const completion = await client.chat.completions.create({  model: "@openai/gpt-5.3-codex",  messages: [{ role: "user", content: "Explain vector cache routing." }],});console.log(completion.choices[0]?.message?.content);

Endpoint

Base URL

https://api.openai.com/v1

Chat completions

https://api.openai.com/v1/chat/completions

Model

gpt-5.3-codex

Auth env

OPENAI_API_KEY

GPT-5.3 Codex FAQ

How much does the GPT-5.3 Codex API cost?

Through OpenAI, GPT-5.3 Codex costs $1.75 per 1M input tokens and $14.00 per 1M output tokens.

What is the context window of GPT-5.3 Codex?

GPT-5.3 Codex accepts up to 400K tokens of context and returns up to 128K output tokens on OpenAI.

What can GPT-5.3 Codex do?

GPT-5.3 Codex supports chat, function calling, image input and reasoning. It accepts text, image and PDF input.

How do I call GPT-5.3 Codex through Everstack?

Point any OpenAI-compatible SDK at your Everstack gateway and set the model to @openai/gpt-5.3-codex. Everstack adds retries, provider fallback, caching, per-tenant budgets and OpenTelemetry traces for every request.