🧠

OpenAI GPT

GPT (Generative Pre-trained Transformer) is OpenAI's flagship large language model line — the model family behind ChatGPT and the default engine powering a huge share of AI features built into other products. It's the single most-used AI model line in the world today, with roughly 81.4% usage share across developer and product integrations, far ahead of any competitor. GPT models (GPT-4o, GPT-5 and their successors) are known for broad general-purpose capability across chat, coding, reasoning, and multimodal input, making them the go-to default choice for most developers building AI-powered apps.

Quick facts
Made by: OpenAI
Access: Proprietary — paid usage-based API (platform.openai.com), plus free/paid tiers inside the ChatGPT app
Context window: Roughly 128K tokens on GPT-4o class models, up to 400K+ on newer GPT-5-class models (varies by exact version — check the model docs)
Strengths: Broad general capability, strong multimodal (text/image/audio) support, huge tool/ecosystem support, reliable function calling
Primary use case: General-purpose AI assistant tasks — chat, coding help, summarization, agentic tool use, and app integrations via API

Jump to: Example Getting started Best for

Example

The GPT API is called through OpenAI's official Python SDK. This sends a prompt to gpt-4o using the Chat Completions API and prints the reply.

from openai import OpenAI

client = OpenAI(api_key="YOUR_API_KEY")

response = client.chat.completions.create(
    model="gpt-4o",
    messages=[
        {"role": "user", "content": "Explain what a REST API is in two sentences."}
    ]
)

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

Getting started

Create an OpenAI platform account, generate an API key, install the SDK, then make your first call.

# 1. Create an account and API key at platform.openai.com/api-keys

# 2. install the SDK
pip install openai

# 3. set your key as an environment variable
export OPENAI_API_KEY="your-key-here"

Best for: Teams that want a single dependable default model for almost any AI feature — chat assistants, coding copilots, summarization, and agentic workflows — backed by the largest ecosystem of SDKs, integrations, and community examples of any model family.