How to beginner · 3 min read

How to migrate from OpenAI v0 to v1 SDK

Quick answer

To migrate from the OpenAI v0 SDK to v1, replace calls like openai.ChatCompletion.create() with the new client pattern using OpenAI from openai. Instantiate the client with OpenAI(api_key=os.environ["OPENAI_API_KEY"]) and call client.chat.completions.create() with the updated model names such as gpt-4o.

PREREQUISITES

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

Setup

Install the latest OpenAI Python SDK version 1 or higher and set your API key as an environment variable.

Run pip install --upgrade openai to upgrade.
Set your API key in your shell: export OPENAI_API_KEY='your_api_key_here' (Linux/macOS) or setx OPENAI_API_KEY "your_api_key_here" (Windows).

bash

pip install --upgrade openai

Step by step migration

Replace the old v0 usage with the new v1 client pattern. The new SDK uses an explicit OpenAI client instance and updated method calls.

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": "Hello from v1 SDK!"}]
)

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

output

Hello from v1 SDK!

Common variations

You can migrate async code by using asyncio and await with the OpenAI client. Also, update model names to current ones like gpt-4o or gpt-4o-mini. Streaming is supported via stream=True in the create() call.

python

import os
import asyncio
from openai import OpenAI

async def main():
    client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])
    response = await client.chat.completions.acreate(
        model="gpt-4o",
        messages=[{"role": "user", "content": "Async hello!"}]
    )
    print(response.choices[0].message.content)

asyncio.run(main())

output

Async hello!

Troubleshooting

If you get AttributeError or ImportError, ensure you have upgraded to openai>=1.0. If your environment variable OPENAI_API_KEY is missing, the client will fail to authenticate. Also, verify you are using the correct model names like gpt-4o instead of deprecated ones.

✅

Key Takeaways

Use the new OpenAI client from the openai package for v1 SDK.
Replace openai.ChatCompletion.create() with client.chat.completions.create().
Always load your API key from os.environ["OPENAI_API_KEY"].
Update model names to current ones like gpt-4o.
For async or streaming, use the new async methods and parameters in the v1 SDK.

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

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