LLM Reference
OpenAI API

Using GPT-4.5 on OpenAI API

Implementation guide · GPT-4.5 · OpenAI

Serverless

OpenAI API exposes GPT-4.5 through model ID gpt-4-5. Use the setup steps, sourced pricing, capabilities, and official provider links below to validate this route before deployment.

Last refreshed 2026-05-20. Next refresh: weekly.

Quick Start

  1. 1
    Create an account at OpenAI API and generate an API key.
  2. 2
    Use the OpenAI API SDK or REST API to call gpt-4-5 — see the documentation for request format.

Code Examples

Install
pip install openai
API key
OPENAI_API_KEY
Model ID
gpt-4-5

Use the model slug directly, e.g. "gpt-4o" or "gpt-4.1-mini".

import os
from openai import OpenAI

client = OpenAI()  # reads OPENAI_API_KEY from env
response = client.chat.completions.create(
    model="gpt-4-5",
    messages=[{"role": "user", "content": "Hello"}]
)
print(response.choices[0].message.content)

Pricing on OpenAI API

Capabilities

VisionMultimodalJSON / Tool useStructured OutputsCode ExecutionFine-tuning

About GPT-4.5

Improved GPT-4 variant released March 2026. Enhanced performance over GPT-4o with better reasoning and code generation.

Model Specs

Released2025-02-27
Context8k
Knowledge cutoff2025-04

Provider

OpenAI API
OpenAI API

OpenAI

San Francisco, California, United States