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Responses API backward compatibility

Q: Responses API backward compatibility

The OpenAI Responses API in SDK v1+ uses client.chat.completions.create() which returns a response object with choices accessible via response.choices[0].message.content. To maintain backward compatibility with older code, adapt legacy calls to this pattern and avoid deprecated methods like openai.ChatCompletion.create(). Always use the latest SDK patterns for stable integration.

Quick answer

The OpenAI Responses API in SDK v1+ uses client.chat.completions.create() which returns a response object with choices accessible via response.choices[0].message.content. To maintain backward compatibility with older code, adapt legacy calls to this pattern and avoid deprecated methods like openai.ChatCompletion.create(). Always use the latest SDK patterns for stable integration.

PREREQUISITES

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

Setup

Install the latest OpenAI Python SDK (v1 or higher) and set your API key as an environment variable to ensure compatibility with the current Responses API.

bash

pip install --upgrade openai

Step by step

Use the current SDK pattern to create chat completions and access response content. This example shows the recommended way to call the Responses API and extract the text.

python

import os
from openai import OpenAI

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

response = client.chat.completions.create(
    model="gpt-4o-mini",
    messages=[{"role": "user", "content": "Hello, how do I maintain backward compatibility with the Responses API?"}]
)

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

output

The OpenAI Responses API uses the new SDK pattern with response.choices[0].message.content for output text.

Common variations

For asynchronous calls, use async with await on client.chat.completions.create(). Streaming responses require iterating over the streamed chunks. Avoid deprecated methods like openai.ChatCompletion.create() to ensure forward compatibility.

python

import asyncio
import os
from openai import OpenAI

async def async_chat():
    client = OpenAI(api_key=os.environ["OPENAI_API_KEY"])
    stream = await client.chat.completions.create(
        model="gpt-4o-mini",
        messages=[{"role": "user", "content": "Stream this response."}],
        stream=True
    )
    async for chunk in stream:
        print(chunk.choices[0].delta.content or "", end="", flush=True)

asyncio.run(async_chat())

output

Streaming response text printed token by token without deprecated calls.

Troubleshooting

If you see AttributeError on ChatCompletion.create(), you are using deprecated SDK v0 syntax; switch to client.chat.completions.create().
Ensure your environment variable OPENAI_API_KEY is set correctly.
Check that your model name is current (e.g., gpt-4o-mini) as older models may be deprecated.

✅

Key Takeaways

Always use client.chat.completions.create() with the latest OpenAI SDK for Responses API calls.
Access response text via response.choices[0].message.content to maintain compatibility.
Avoid deprecated methods like openai.ChatCompletion.create() to prevent runtime errors.
Use environment variables for API keys to keep code secure and portable.
Update model names regularly to ensure support and best performance.

Verified 2026-04 · gpt-4o-mini

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