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This quickstart guide will help you make your first API call using the OpenAI Python SDK. We’ll cover both the Responses API (recommended) and the Chat Completions API.

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Prerequisites

Before you begin, make sure you have:
1

Installed the SDK

pip install openai
See the Installation guide for more details.
2

Set up your API key

export OPENAI_API_KEY="sk-proj-..."
Get your API key from the OpenAI dashboard.

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Using the Responses API

The Responses API is the primary way to interact with OpenAI models. It provides a simplified interface for generating text.

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Basic Text Generation

Create your first response: 
import os
from openai import OpenAI

client = OpenAI(
    # This is the default and can be omitted
    api_key=os.environ.get("OPENAI_API_KEY"),
)

response = client.responses.create(
    model="gpt-5.2",
    instructions="You are a coding assistant that talks like a pirate.",
    input="How do I check if a Python object is an instance of a class?",
)

print(response.output_text)
The api_key parameter is optional. If not provided, the client automatically reads from the OPENAI_API_KEY environment variable.

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Simple Input

For straightforward queries, you can pass just the input text: 
response = client.responses.create(
    model="gpt-5.2",
    input="Explain quantum computing in simple terms.",
)

print(response.output_text)

​
Vision Input

Process images alongside text: 
response = client.responses.create(
    model="gpt-5.2",
    input=[
        {
            "role": "user",
            "content": [
                {"type": "input_text", "text": "What is in this image?"},
                {
                    "type": "input_image",
                    "image_url": "https://upload.wikimedia.org/wikipedia/commons/thumb/d/d5/2023_06_08_Raccoon1.jpg/1599px-2023_06_08_Raccoon1.jpg"
                },
            ],
        }
    ],
)

print(response.output_text)

​
Using the Chat Completions API

The Chat Completions API is the previous standard for generating text, and is supported indefinitely.

​
Basic Chat Completion

from openai import OpenAI

client = OpenAI()

completion = client.chat.completions.create(
    model="gpt-5.2",
    messages=[
        {"role": "developer", "content": "Talk like a pirate."},
        {
            "role": "user",
            "content": "How do I check if a Python object is an instance of a class?",
        },
    ],
)

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

​
Message Roles

The Chat Completions API uses different message roles:
  • developer: System-level instructions for the model’s behavior
  • user: User messages in the conversation
  • assistant: Previous assistant responses (for conversation history)
completion = client.chat.completions.create(
    model="gpt-5.2",
    messages=[
        {"role": "developer", "content": "You are a helpful Python tutor."},
        {"role": "user", "content": "What is a list comprehension?"},
        {"role": "assistant", "content": "A list comprehension is a concise way to create lists..."},
        {"role": "user", "content": "Can you show me an example?"},
    ],
)

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

​
Streaming Responses

Stream responses in real-time for a better user experience: 
from openai import OpenAI

client = OpenAI()

stream = client.responses.create(
    model="gpt-5.2",
    input="Write a one-sentence bedtime story about a unicorn.",
    stream=True,
)

for event in stream:
    print(event)

​
Async Usage

For async applications, use AsyncOpenAI instead of OpenAI: 
import os
import asyncio
from openai import AsyncOpenAI

client = AsyncOpenAI(
    # This is the default and can be omitted
    api_key=os.environ.get("OPENAI_API_KEY"),
)

async def main() -> None:
    response = await client.responses.create(
        model="gpt-5.2",
        input="Explain disestablishmentarianism to a smart five year old.",
    )
    print(response.output_text)

asyncio.run(main())
The async client provides identical functionality to the sync client, but all methods use await.

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Error Handling

Handle API errors gracefully: 
import openai
from openai import OpenAI

client = OpenAI()

try:
    response = client.responses.create(
        model="gpt-5.2",
        input="Hello, world!",
    )
    print(response.output_text)

except openai.APIConnectionError as e:
    print("The server could not be reached")
    print(e.__cause__)  # an underlying Exception, likely raised within httpx.

except openai.RateLimitError as e:
    print("A 429 status code was received; we should back off a bit.")

except openai.APIStatusError as e:
    print("Another non-200-range status code was received")
    print(e.status_code)
    print(e.response)

​
Error Types

The SDK provides specific exception types for different errors:
Status CodeError Type
400BadRequestError
401AuthenticationError
403PermissionDeniedError
404NotFoundError
422UnprocessableEntityError
429RateLimitError
≥500InternalServerError
N/AAPIConnectionError

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Common Configuration

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Timeouts

Set custom timeout values: 
from openai import OpenAI

# Set default timeout for all requests (default is 10 minutes)
client = OpenAI(timeout=20.0)  # 20 seconds

# Override per-request
client.with_options(timeout=5.0).responses.create(
    model="gpt-5.2",
    input="Quick response please!",
)

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Retries

Configure retry behavior: 
from openai import OpenAI

# Configure default retries (default is 2)
client = OpenAI(max_retries=0)  # Disable retries

# Override per-request
client.with_options(max_retries=5).responses.create(
    model="gpt-5.2",
    input="Important request - retry if it fails",
)
Certain errors (connection errors, 408, 409, 429, and ≥500) are automatically retried with exponential backoff.

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Custom Base URL

Use a custom API endpoint: 
from openai import OpenAI

client = OpenAI(
    base_url="http://my.test.server.example.com:8083/v1",
)

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Next Steps

Now that you’ve made your first API call, explore more advanced features:

Responses API

Learn more about the Responses API

Chat Completions

Explore the Chat Completions API

Streaming

Master streaming responses

Error Handling

Handle errors like a pro

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