OpenAI: GPT-5 Codex
openai/gpt-5-codex
Access GPT-5 Codex from OpenAI using Puter.js AI API.
Get Started// npm install @heyputer/puter.js
import { puter } from '@heyputer/puter.js';
puter.ai.chat("Explain quantum computing in simple terms", {
model: "openai/gpt-5-codex"
}).then(response => {
document.body.innerHTML = response.message.content;
});
<html>
<body>
<script src="https://js.puter.com/v2/"></script>
<script>
puter.ai.chat("Explain quantum computing in simple terms", {
model: "openai/gpt-5-codex"
}).then(response => {
document.body.innerHTML = response.message.content;
});
</script>
</body>
</html>
# pip install openai
from openai import OpenAI
client = OpenAI(
base_url="https://api.puter.com/puterai/openai/v1/",
api_key="YOUR_PUTER_AUTH_TOKEN",
)
response = client.chat.completions.create(
model="openai/gpt-5-codex",
messages=[
{"role": "user", "content": "Explain quantum computing in simple terms"}
],
)
print(response.choices[0].message.content)
curl https://api.puter.com/puterai/openai/v1/chat/completions \
-H "Content-Type: application/json" \
-H "Authorization: Bearer YOUR_PUTER_AUTH_TOKEN" \
-d '{
"model": "openai/gpt-5-codex",
"messages": [
{"role": "user", "content": "Explain quantum computing in simple terms"}
]
}'
Model Card
GPT-5 Codex is a version of GPT-5 optimized for agentic coding tasks in Codex or similar environments. It's designed for software engineering workflows with enhanced code generation capabilities.
Context Window 400K
tokens
Max Output 128K
tokens
Input Cost $1.25
per million tokens
Output Cost $10
per million tokens
Release Date Jul 1, 2025
Output Speed 213
tokens / sec
Latency 14.19s
time to first token
Model Playground
Try GPT-5 Codex instantly in your browser.
This playground uses the Puter.js AI API — no API keys or setup required.
Benchmarks
How GPT-5 Codex performs on standard evaluations.
| Benchmark | Score |
|---|---|
| GPQA Diamond Graduate-level science Q&A | 83.7% |
| Humanity's Last Exam Cross-domain reasoning | 25.6% |
| LiveCodeBench Recent coding problems | 84.0% |
| SciCode Scientific programming | 40.9% |
| AIME 2025 Advanced math exam | 98.7% |
| IFBench Instruction following | 74.1% |
| LCR Long-context reasoning | 69.0% |
| Terminal-Bench Hard Agentic terminal tasks | 37.9% |
| τ²-Bench Tool use / agents | 86.8% |
Scores sourced from Artificial Analysis.
Find other OpenAI models →
GPT-5.4 Mini
GPT-5.4 Mini is OpenAI's fast, efficient distillation of GPT-5.4, significantly improving over GPT-5 Mini across coding, reasoning, multimodal understanding, and tool use while running 2x faster. It approaches GPT-5.4-level performance on several benchmarks and features a 400k context window.
ChatGPT-5.4 Nano
GPT-5.4 Nano is the smallest and cheapest model in the GPT-5.4 family, offering a 400k context window at just $0.20/1M input tokens. It excels at classification, data extraction, ranking, and coding sub-agent tasks, outperforming the previous GPT-5 Mini on SWE-Bench Pro (52.4% vs 45.7%). It's ideal for high-volume, low-latency workloads and as a fast sub-agent in multi-model architectures.
ChatGPT-5.4
GPT-5.4 is OpenAI's latest frontier model released on March 5, 2026, designed for complex professional work with a 1.05M token context window, built-in computer-use capabilities, and improved coding from GPT-5.3-Codex. It is 33% less likely to make factual errors per claim compared to GPT-5.2 and scores 83% on OpenAI's GDPval knowledge work benchmark.
Frequently Asked Questions
You can access GPT-5 Codex by OpenAI through Puter.js AI API. Include the library in your web app or Node.js project and start making calls with just a few lines of JavaScript — no backend and no configuration required. You can also use it with Python or cURL via Puter's OpenAI-compatible API.
Yes, it is free if you're using it through Puter.js. With the User-Pays Model, you can add GPT-5 Codex to your app at no cost — your users pay for their own AI usage directly, making it completely free for you as a developer.
| Price per 1M tokens | |
|---|---|
| Input | $1.25 |
| Output | $10 |
GPT-5 Codex was created by OpenAI and released on Jul 1, 2025.
GPT-5 Codex supports a context window of 400K tokens. For reference, that is roughly equivalent to 800 pages of text.
GPT-5 Codex can generate up to 128K tokens in a single response.
Yes — the GPT-5 Codex API works with any JavaScript framework, Node.js, or plain HTML through Puter.js. Just include the library and start building. See the documentation for more details.
Get started with Puter.js
Add GPT-5 Codex to your app without worrying about API keys or setup.
Read the Docs View Tutorials