How to Build a Native macOS App That Connects to GPT-5 & Claude Opus
Z
Zack Saadioui
8/10/2025
How to Build a Native macOS App That Connects to GPT-5 & Claude Opus
What's up, developers! So, you've been hearing all the buzz about GPT-5 & Claude Opus. These large language models are ridiculously powerful, & if you're a macOS developer, you're probably wondering how you can get in on the action. Here's the thing: building a native macOS app that taps into the power of these AI models is not as hard as you might think. Honestly, it's pretty cool what you can build with a little bit of SwiftUI knowledge & the right APIs.
In this guide, I'm going to walk you through everything you need to know to build your own native macOS app that connects to both GPT-5 & Claude Opus. We'll cover everything from getting your API keys to building a slick SwiftUI interface & handling streaming responses for that real-time chatbot feel.
First Things First: Getting Your API Keys
Before we can start writing any code, you'll need to get your hands on some API keys. These are basically your secret passwords that let your app talk to the GPT-5 & Claude Opus APIs.
For GPT-5: You'll need to head over to the OpenAI platform & create an account. Once you're in, you can generate an API key from your dashboard. Keep this key safe! Don't just paste it into your code where everyone can see it. We'll talk more about how to store it securely later.
For Claude Opus: Similarly, you'll need to get access to the Anthropic API. You might need to join a waitlist, but once you're in, you'll be able to get an API key.
Setting Up Your Xcode Project
Alright, let's get our hands dirty. Fire up Xcode & create a new macOS app project. Make sure you select SwiftUI for the interface. Once your project is created, we'll need to add a couple of dependencies to make our lives easier.
For connecting to the OpenAI API, there's a handy Swift package called
1
OpenAISwift
. To add it, go to
1
File > Add Package Dependencies
& paste in this URL:
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https://github.com/adamrushy/OpenAISwift.git
.
For the Claude API, we've got a great open-source option called
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SwiftClaude
. You can add it using the same process with its GitHub URL:
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https://github.com/GeorgeLyon/SwiftClaude
. This library is a real game-changer because it’s built with SwiftUI in mind.
Building the User Interface with SwiftUI
Now for the fun part: building the UI. We're going to keep it simple for this tutorial: a text input field for the user to type their prompt, a send button, & a display area for the AI's response.