LLM Reference
OpenAI API

GPT-5 Codex on OpenAI API

GPT-5 · OpenAI

Serverless

Last refreshed 2026-05-10. Next refresh: weekly.

Why use GPT-5 Codex on OpenAI API?

OpenAI API offers GPT-5 Codex with pay-as-you-go pricing at $1.25/1M input tokens. OpenAI is a leading AI research and deployment company dedicated to developing safe and beneficial artificial general intelligence (AGI) for humanity.

Compare GPT-5 Codex across 3 providers to find the best fit for your use case
Input / 1M
$1.25
Output / 1M
$10.00
Cache
read $0.125
Batch
Not sourced

Setup recipe

Python + curl
Install
pip install openai
Auth
export OPENAI_API_KEY=...
Call
import os
from openai import OpenAI
client = OpenAI()  # reads OPENAI_API_KEY from env
response = client.chat.completions.create(
Model ID
gpt-5-codex

Request example

import os
from openai import OpenAI

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

Gotchas

  • Use the model slug directly, e.g. "gpt-4o" or "gpt-4.1-mini".
  • The examples expect OPENAI_API_KEY; rename it only if your application config maps the new variable.

Compare GPT-5 Codex Across Providers

ProviderInput (per 1M)Output (per 1M)
Vercel AI Gateway$1.25$10.00
OpenRouter$1.25$10.00
OpenAI API$1.25$10.00

Pricing

TypePrice (per 1M)
Input tokens$1.25
Output tokens$10.00

Capabilities

VisionMultimodalJSON / Tool useStructured OutputsCode Execution

About GPT-5 Codex

GPT-5 Codex is OpenAI's coding-specialized variant of GPT-5, optimized for software engineering workflows, code generation, and agentic coding tasks at 400K context.

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Model Specs

Released2025-10-01
Context400k
ArchitectureDecoder Only
Knowledge cutoff2024-09