ChatGPT gives you two very different ways to build an AI that works for you. Here's what each one is, which to start with, and how to build your first one with no code.
If you've spent any time in ChatGPT, you've probably wondered whether you could build your own version of it. One that already knows your business, writes in your voice, and handles the same tasks you keep asking for over and over. You can. And in 2026, OpenAI actually gives you two ways to do it.
The problem is that those two ways get talked about as if they're the same thing, and they really aren't. One is a custom assistant that waits for you to chat with it. The other is an agent that goes off and does multi-step work on its own. Picking the wrong one wastes your time, or your money. So this guide walks you through both, shows you how to build the beginner-friendly one step by step with no code, and helps you understand how OpenAI's approach stacks up against Claude and Gemini.