How to beginner · 3 min read

How to use GPT-4o for code generation

Q: How to use GPT-4o for code generation

Use the gpt-4o model via the OpenAI Python SDK to generate code by sending a chat completion request with a coding prompt. Set your API key in os.environ["OPENAI_API_KEY"] and call client.chat.completions.create() with model="gpt-4o" and appropriate messages.

Quick answer

Use the gpt-4o model via the OpenAI Python SDK to generate code by sending a chat completion request with a coding prompt. Set your API key in os.environ["OPENAI_API_KEY"] and call client.chat.completions.create() with model="gpt-4o" and appropriate messages.

PREREQUISITES

Python 3.8+
OpenAI API key (free tier works)
pip install openai>=1.0

Setup

Install the official OpenAI Python SDK and set your API key as an environment variable for secure authentication.

bash

pip install openai>=1.0

Step by step

This example shows how to generate Python code using gpt-4o. It sends a prompt asking for a function to reverse a string and prints the AI-generated code.

python

import os
from openai import OpenAI

client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])

response = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "user", "content": "Write a Python function to reverse a string."}
    ]
)

print(response.choices[0].message.content)

output

def reverse_string(s):
    return s[::-1]

Common variations

Streaming output: Use stream=True to receive tokens as they are generated for faster feedback.
Async usage: Use async clients or frameworks to integrate code generation in asynchronous workflows.
Different models: Use gpt-4o-mini for faster, cheaper code generation with slightly reduced quality.

python

import os
import asyncio
from openai import OpenAI

async def async_code_generation():
    client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])
    stream = await client.chat.completions.acreate(
        model="gpt-4o",
        messages=[{"role": "user", "content": "Write a Python function to check if a number is prime."}],
        stream=True
    )
    async for chunk in stream:
        print(chunk.choices[0].delta.content or '', end='', flush=True)

asyncio.run(async_code_generation())

output

def is_prime(n):
    if n <= 1:
        return False
    for i in range(2, int(n**0.5) + 1):
        if n % i == 0:
            return False
    return True

Troubleshooting

If you get 401 Unauthorized, verify your OPENAI_API_KEY environment variable is set correctly.
If the model returns irrelevant text, try refining your prompt with explicit instructions.
For rate limits, consider exponential backoff or upgrading your OpenAI plan.

✅

Key Takeaways

Use the OpenAI Python SDK with gpt-4o for high-quality code generation.
Set OPENAI_API_KEY in your environment to authenticate securely.
Streaming and async calls improve responsiveness in interactive applications.
Prompt clarity directly impacts the quality of generated code.
Check API key and usage limits if you encounter authentication or rate errors.

Verified 2026-04 · gpt-4o, gpt-4o-mini

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