Unlock Custom AI: How to Create and Run GPTs Without a ChatGPT Plus Subscription

OpenAI’s Custom GPTs are powerful, specialized versions of ChatGPT that can be tailored with specific instructions, knowledge bases, and capabilities. However, the catch for many users is the requirement of a paid ChatGPT Plus subscription to create them.

The good news? You can achieve the same core functionality—a specialized, embeddable AI assistant powered by the latest large language models (LLMs)—by using alternative platforms and the OpenAI Assistant API.

Here is a step-by-step guide to creating your own custom GPT-like assistant for free, focusing on the highly effective method demonstrated in the provided tutorial.

The Free Alternative: Using the OpenAI Assistant API via a No-Code Platform

The official ChatGPT GPT Builder is a simple, no-code way to build custom GPTs, but it's paywalled. An excellent workaround is to use a free, open-source tool that connects to the underlying technology: The OpenAI Assistant API. This API is a powerful set of tools that allows developers to create specialized AI applications, which other platforms can expose through a simple interface.

The video you provided highlighted one such tool: Open Custom GPT.

What You Will Need

  1. An OpenAI Account: You will need a standard free OpenAI account to access the API key.

  2. An OpenAI API Key: You must generate an API key from your OpenAI dashboard. While the API itself is not free, its pricing is usage-based (pay-as-you-go) and incredibly low for light use, often amounting to just cents for testing and small projects.

  3. A No-Code Platform: A free/open-source tool like Open Custom GPT or similar alternatives that connect to the Assistants API.

Step-by-Step Guide: Building Your Custom Assistant

Step 1: Get Your OpenAI API Key

  1. Log into your OpenAI account and navigate to the API keys section.

  2. Create a New Secret Key and be sure to copy it immediately, as it will not be shown again. This key is what the third-party tool uses to connect your custom assistant to the power of the OpenAI model (like GPT-4, if available in the API).

Step 2: Set up Your Assistant in the Platform

  1. Access your chosen no-code platform (e.g., Open Custom GPT).

  2. The platform will first require you to enter your OpenAI API key in the designated settings area.

  3. Once connected, look for an option to "Create New Assistant" or "Create New GPT."

Step 3: Define Your Custom Instructions

This is the most critical part, as it dictates the behavior of your AI assistant.

  • Name & Purpose: Give your assistant a clear, descriptive name (e.g., "Legal Document Summarizer").

  • Custom Instructions: Enter the precise rules, persona, and goals for the AI. This replaces the "Configure" tab in the official ChatGPT Builder.

    • Example: "You are a friendly but rigorous technical documentation expert. Your primary goal is to answer questions based only on the uploaded files. If the answer is not in the knowledge base, you must state, 'I cannot find the answer in my current knowledge base.'"

Step 4: Upload Your Knowledge Base (Retrieval)

To make your AI specialized, you need to give it custom information.

  • Look for the Knowledge or Retrieval setting.

  • Upload your files (PDFs, text files, CSVs, etc.) that contain the specific data you want the AI to reference. By enabling retrieval, the AI can search these documents for answers, just like an official custom GPT.

Step 5: Enable Capabilities (Optional)

If the platform supports it, you can enable additional functions:

  • Code Interpreter: Allows the AI to write and run code (for data analysis, math, etc.).

  • Functions/Actions: Connect the AI to external APIs or tools.

Step 6: Submit and Test

Once your settings are complete, submit the configuration to create your assistant. You can then immediately begin testing it within the platform's chat interface.

The Power of This Free Method: Embed and Monetize

Using the Assistants API via a third-party builder offers two significant advantages that even paid ChatGPT Plus users may not get:

1. Public Access and Embedding

Unlike official custom GPTs, which are locked behind the ChatGPT platform, assistants built this way can often be:

  • Embedded directly onto your own website, blog, or application using a simple iframe code.

  • Shared publicly via a direct link. Crucially, your users do not need a ChatGPT Plus subscription to interact with it.

2. Direct Monetization

Since the assistant is running on your own API key and can be embedded, you gain control over the user experience and payment:

  • Add a Paywall: You can place the embedded assistant behind a simple membership or paywall on your website, allowing you to charge a subscription fee for access.

  • Control Profit: You keep 100% of the revenue, paying only the very small, usage-based fees to OpenAI for the underlying API calls.

This strategy effectively breaks the subscription barrier, giving you a powerful, customized, and potentially monetizable AI tool without the mandatory monthly fee.

Custom GPTFrancesca Tabor