How I Build Apps With ChatGPT Codex, React Native, and GitHub
I’ve been building an app lately, and my workflow has changed completely. Using ChatGPT Codex, React Native, GitHub Codespaces, and GitHub Copilot has accelerated my programming by a ton. The stack gives me high control and technical flexibility, while still keeping me fast and efficient.
Unlike tools like Replit or Firebase Studio, I can choose the tech stack and database I want. At the same time, I can move quickly, even from my phone. I can write a complex task in ChatGPT Codex, let the agent code it, and later check the diff in GitHub. About 95% of the time, I don’t touch the code—I just merge it. If something feels off, I rephrase the task and let Codex start fresh.
Why React Native Makes This Work So Well
React Native is a super simple stack. Codex handles the context easily and makes solid decisions based on the codebase. That simplicity boosts efficiency.
With Expo, testing is rapid. I can push changes and immediately try the latest version of my app on my phone—no TestFlight setup, no delays. That speed lets me pressure test the user experience constantly.
Switching Between Codex and Codespaces
I’d say 80% of my work happens through ChatGPT Codex. But when I need faster iteration or deep debugging, I switch to Codespaces with Copilot.
Codex is great for formulating tasks and letting it run in the background. But when I need to get the stack into place or troubleshoot tricky bugs, Codespaces + Copilot is faster. I get real-time console output from Expo Go, can accept or reject suggestions immediately, and keep the loop tight.
So:
Codex → best for larger, complex tasks or when I’m not actively coding.
Codespaces + Copilot → best for debugging, stack setup, or rapid iteration.
Progress Without Heavy Time Investment
The best part is how lightweight this feels. I still work full-time, but I can sneak in quick prompts during the day. Codex handles the coding, and by the evening I’ve made real progress in my app—without heavy focus or hours of effort.
Why Expo Is a Game Changer
Expo itself deserves a shout-out. The cloud build process is seamless: I type one command, and Expo builds and even submits the app to the App Store. No Xcode, no local setup nightmares.
Back in the Cordova days, setting up builds and submissions was painful. Now, it’s detached and smooth. I can trigger a build in Codespaces, type my credentials, and that’s it. The rest happens in the cloud.
Wrapping It Up
This workflow feels like a huge leap forward. App development is faster, smoother, and less painful than ever. Codex, Copilot, React Native, Codespaces, and Expo together create an environment where I can build high-quality apps—without losing flexibility, without wasting time, and often straight from my phone.