A Beginner’s Guide to Using the ChatGPT API in 2024

Nitesh Dan Charan
7 min readDec 22, 2023

This guide walks you through the basics of the ChatGPT API, demonstrating its potential in natural language processing and AI-driven communication.

Since it first came out in November 2022, ChatGPT has caught the attention of people worldwide. This amazing AI chatbot is really good at understanding regular language commands and generating responses that sound a lot like human conversation, covering a wide range of topics.

The introduction of advanced language models like GPT-4 has brought about exciting new possibilities in the world of natural language processing.

Thanks to OpenAI’s release of the ChatGPT API, we can now easily incorporate conversational AI features into our applications. In this beginner’s guide, we’ll take a closer look at what the ChatGPT API offers and how you can start using it with a Python client.

What is GPT?

What is GPT?

GPT, which stands for Generative Pre-trained Transformer, is a set of language models created by OpenAI. These models, ranging from GPT-1 to GPT-4, undergo training on extensive text data and can be fine-tuned for specific language-related tasks.

They are particularly good at producing logical text by predicting what words come next. ChatGPT, an AI designed for conversation based on these models, engages in natural language interactions.

It is trained to be secure, dependable, and informative, and its knowledge is current up to March 2023.

What is the ChatGPT API?

An API, or Application Programming Interface, serves as a bridge enabling communication between two software programs. APIs expose specific functions and data from one application to others.

For instance, the Twitter API enables developers to retrieve user profiles, tweets, trends, and more from Twitter, allowing them to construct their own applications using that information.

The ChatGPT API provides access to OpenAI’s conversational AI models such as GPT-4, GPT-4 turbo, GPT-3, etc. It enables us to incorporate these language models into our applications using the API.

There are numerous potential applications where these APIs can add interesting functionality and features to benefit users, including:

  1. Developing chatbots and virtual assistants
  2. Streamlining customer support processes
  3. Generating content such as emails, reports, and more
  4. Providing answers to domain-specific questions

Key Features of the ChatGPT API

Let’s explore some compelling features that make the ChatGPT API a valuable choice for your project:

  1. Natural Language Understanding: ChatGPT showcases remarkable prowess in comprehending natural language. Built on the GPT-3 architecture, it can interpret a wide array of natural language inputs, be it questions, commands, or statements. Its training on an extensive corpus of text data equips it to recognize various linguistic nuances, resulting in accurate and contextually relevant responses.
  2. Contextual Response Generation: The API excels in crafting text that not only flows coherently but is also contextually relevant. This means ChatGPT can generate responses that seamlessly fit into the ongoing conversation, staying aligned with the provided context. Its ability to handle long sequences of text ensures an understanding of dependencies within a conversation, guaranteeing responses that are not only accurate but also meaningful within the given context.
  3. Key Capabilities:
  • Natural Language Understanding: ChatGPT understands natural language inputs effectively.
  • Contextual Response Generation: It produces responses that align with the flow and context of the conversation.
  • Answering Follow-up Questions: Capable of addressing subsequent questions based on the ongoing conversation.
  • Support for Conversational Workflows: Designed to seamlessly integrate into interactive and dynamic conversational scenarios.

Choosing the ChatGPT API for your project can leverage these features, offering a sophisticated and context-aware conversational experience for users.

How to use the ChatGPT API

The OpenAI Python API library provides a straightforward and effective means of engaging with OpenAI’s REST API within any Python 3.7+ application.

This comprehensive guide is designed to assist you in gaining a clear understanding of how to efficiently utilize the library.

!pip install openai


To use the library, you’ll need to import it and create an OpenAI client:

from openai import OpenAI
client = OpenAI(api_key="...")

You can generate a key by signing into platform.openai.com

Once you have the key, you can then make API calls, such as creating chat completions:

chat_completion = client.chat.completions.create(
"role": "user",
"content": "What is Machine Learning?",

The library also supports streaming responses using Server-Side Events (SSE). Here’s an example of how to stream responses:

from openai import OpenAI
client = OpenAI(api_key="...")
stream = client.chat.completions.create(
messages=[{"role": "user", "content": "what is machine learning?"}],
for part in stream:
print(part.choices[0].delta.content or "")

OpenAI Models and Pricing

OpenAI provides a variety of AI models accessible through their API, each with distinct capabilities, pricing structures, and intended use cases.

The premier model, GPT-4, stands as the most advanced and costly option, starting at $0.03 per 1,000 tokens for input and $0.06 per 1,000 tokens for output. Renowned for its state-of-the-art natural language processing, GPT-4 can comprehend and generate human-like text, supporting up to 128,000 tokens of context. The GPT-4 family includes the base GPT-4 model and GPT-4–32k, which employs 32,000 tokens of context.

The recently introduced GPT-4 turbo model boasts a 128k context length, incorporates vision support, and outperforms GPT-4. Remarkably, its pricing is set at just $0.01 per 1,000 tokens for input and $0.03 per 1,000 tokens for output.

For more cost-effective natural language processing, OpenAI offers the GPT-3.5 family of models. GPT-3.5 Turbo, optimized for conversational applications with 16,000 tokens of context, is priced at $0.0010 per 1,000 input tokens and $0.0020 per 1,000 output tokens. GPT-3.5 Turbo Instruct, an instruct model with 4,000 tokens of context, is priced slightly higher at $0.0015 per 1,000 input tokens and $0.0020 per 1,000 output tokens.

Beyond core language models, OpenAI extends additional capabilities through their API. The Assistants API simplifies AI assistant development with features like retrieval and code interpretation. Image models handle image generation and editing, while embedding models represent text as numerical vectors. Fine-tuning options are also available for tailoring models to specific applications.

Developers can leverage OpenAI’s potent AI models through a flexible pay-as-you-go API. The choice of model depends on specific application requirements and budget considerations. While GPT-4 offers cutting-edge capabilities at a premium, models like GPT-3.5 strike a balance between performance and cost for many applications. To explore all available models and API pricing, refer to the official documentation.

Flexibility and Customization

The API offers various parameters to customize the behavior of the model according to your application’s requirements:


api_key (str): Your API key for authenticating requests. Required.


model (str): The ID of the model to use, specifying which model to use for completion.


prompt (str): The prompt(s) to generate completions for, typically text.

suffix (str): The suffix that comes after a completion of generated text.


max_tokens (int): The maximum number of tokens to generate in the completion (between 1 and 4096).

stop (str): Up to 4 sequences where the API will stop generating further tokens.

temperature (float): Controls randomness, with values ranging from 0.0 to 2.0. Higher values mean the model takes more risks.

top_p (float): An alternative to sampling with temperature, known as nucleus sampling, with values ranging from 0.0 to 1.0. Higher values mean the model takes more risks.

n (int): Specifies how many completions to generate for each prompt.

stream (bool): Determines whether to stream back partial progress. If set, tokens will be sent as data-only server-sent events as they become available.

Shaping ChatGPT API Behavior

The main message types shaping a chatbot’s behavior are ‘system,’ ‘user,’ and ‘assistant’ messages. System messages help the chatbot keep track of the conversation state, understand context, and determine appropriate responses. User messages provide the conversational input, and assistant messages are the chatbot’s responses.


The ChatGPT API represents a significant advancement in conversational AI, providing a versatile and powerful tool for developers. Its ability to understand and generate natural language, along with its flexibility for integration into various applications, makes it invaluable for creating sophisticated AI-driven solutions.

Whether for building advanced chatbots, automating customer support, generating creative content, or answering specific domain questions, the ChatGPT API offers the necessary tools and capabilities to bring these ideas to life.

With a range of models from GPT-4 to more cost-effective GPT-3.5 variants, developers can select the most suitable tool for their needs. This comprehensive guide serves as an excellent starting point for anyone looking to harness the power of this cutting-edge technology.

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