> ## Documentation Index
> Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt
> Use this file to discover all available pages before exploring further.

# What is ChatGPT

> This article explores ChatGPT, its models, tiers, integration options, and features for users and developers.

Welcome to Section 3 of this lesson. Here, we’ll dive into ChatGPT from the OpenAI platform perspective, exploring its underlying GPT models, available tiers, and integration options.

## Overview

ChatGPT is a conversational AI assistant built on OpenAI’s GPT (Generative Pre-trained Transformer) models.

* Free tier: powered by **GPT-3.5**
* Paid tier (ChatGPT Plus): powered by **GPT-4**
* Mobile access: available via the [ChatGPT iOS app](https://apps.apple.com/app/openai-chatgpt/id6448311069)

<Callout icon="lightbulb" color="#1CB2FE">
  ChatGPT’s training data cuts off in 2021, so it won’t know about events or developments after that year.
</Callout>

## Free Version of ChatGPT

If you already have an [OpenAI account](https://platform.openai.com/), click **Log in** to access the free ChatGPT interface.

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  ![The image shows the ChatGPT interface with sections highlighting examples, capabilities, and limitations of the AI. It includes example prompts and descriptions of what the AI can and cannot do.](https://kodekloud.com/kk-media/image/upload/v1752881502/notes-assets/images/Mastering-Generative-AI-with-OpenAI-What-is-ChatGPT/chatgpt-interface-examples-capabilities-limitations.jpg)
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* **Prompt box**: Enter your text prompt to guide the model’s response.
* **Examples & Capabilities**: Predefined prompts and features you can try.
* **Limitations**: Known model constraints and areas to watch out for.

## Upgrading to ChatGPT Plus

To unlock GPT-4 and additional features:

1. Click **Upgrade to Plus** in the ChatGPT web interface.
2. Enter payment details (\$20/month).
3. Confirm your subscription.

<Callout icon="triangle-alert" color="#FF6B6B">
  ChatGPT Plus subscriptions are billed separately from your OpenAI API usage. Monitor both accounts to avoid unexpected charges.
</Callout>

### Feature Comparison

| Feature         | Free (GPT-3.5) | ChatGPT Plus (GPT-4)          |
| --------------- | -------------- | ----------------------------- |
| Model           | GPT-3.5        | GPT-4 (plus GPT-3.5 option)   |
| Price           | Free           | \$20/month                    |
| Response speed  | Standard       | Faster                        |
| Plugins         | Not available  | Available (e.g., Bing search) |
| Priority access | No             | Yes                           |

For full pricing details, see the [OpenAI Pricing page](https://openai.com/pricing).

## ChatGPT Plus and GPT-4

With ChatGPT Plus, you can:

* Choose between **GPT-3.5** and **GPT-4**
* Leverage **plugins** to connect ChatGPT with external data sources
* Enjoy priority access during peak usage times

## Building Your Own Chatbot

Beyond the ChatGPT UI, you can embed GPT-powered chatbots into your own applications using the [OpenAI API](https://platform.openai.com/docs/api-reference/introduction). This enables you to:

* Automate customer support
* Develop interactive educational tools
* Create AI-driven assistants in web or mobile apps

By the end of this course, you’ll master:

* Prompt design best practices
* Prompt engineering techniques
* Integration workflows with GPT-3.5 and GPT-4

Explore the next sections to start building AI-driven tools with OpenAI’s powerful models.

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  <Card title="Watch Video" icon="video" cta="Learn more" href="https://learn.kodekloud.com/user/courses/mastering-generative-ai-with-openai/module/8a22dad7-381f-463c-9b71-18ca8cda36a4/lesson/d2a0f119-2091-4a29-8400-36f04454ef5c" />
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