GPT-4o Guide 2025: Features, API, and Real-World Uses

from openai import OpenAI

client = OpenAI()  # Uses OPENAI_API_KEY env var

# --- Text completion ---
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "system", "content": "You are a helpful assistant."},
        {"role": "user", "content": "Explain the difference between TCP and UDP in 3 sentences."}
    ],
    max_tokens=300,
)
print(response.choices[0].message.content)

# --- Vision: analyze an image ---
response = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {
            "role": "user",
            "content": [
                {"type": "text", "text": "What's in this image? List any issues you see."},
                {
                    "type": "image_url",
                    "image_url": {
                        "url": "https://example.com/screenshot.png",
                        # Or base64: "url": "data:image/png;base64,{base64_string}"
                    }
                }
            ]
        }
    ],
    max_tokens=500,
)
print(response.choices[0].message.content)

# --- GPT-4o mini for cost-sensitive tasks ---
mini_response = client.chat.completions.create(
    model="gpt-4o-mini",
    messages=[
        {"role": "user", "content": "Classify this support ticket as: billing / technical / general. Reply with one word only. Ticket: 'I can't log in after resetting my password.'"}
    ],
    max_tokens=10,
)
print(mini_response.choices[0].message.content)  # "technical"

# --- Streaming response ---
stream = client.chat.completions.create(
    model="gpt-4o",
    messages=[{"role": "user", "content": "Write a haiku about APIs."}],
    stream=True,
)
for chunk in stream:
    if chunk.choices[0].delta.content is not None:
        print(chunk.choices[0].delta.content, end="", flush=True)