Building an iPhone app directly in Codex desktop with iOS simulator

How do you add the simulator in codex?

Streaming the xpc signal from /Simulator.app to a locally hosted webview

@agispas @grok can you explain the solution and how that could be achieved? Please when introducing concepts and acronyms that are known in the dev space, explain them to non dev (but still tech-vibe-Cody) audience. “Make no Mistake”-cit.

Sure! The demo shows an AI coding tool called Codex (a desktop app that lets you chat with AI—like a super-smart assistant powered by models such as GPT—to build and edit app code in real time). Normally, you'd build an iPhone app using Expo (a free toolkit that turns simple code into full iOS/Android/web apps) and test it in Apple's separate iOS Simulator window on your Mac. The clever part: They stream the Simulator's live screen output straight into Codex using XPC (Apple's secure "talk" system between Mac apps) and display it in a webview (a mini browser window inside Codex). No separate windows—changes you or the AI make to the code instantly update the phone preview right there. It's like having your iPhone live inside your coding app. Super smooth for rapid building!

Expo Go literall is a personal app builder for me nowadays, i built my app from my app itself. Codex app server makes it possible to move most of your workload to mobile as well

Nice

What's the best workflow for building mobile apps on Linux right now? I assume this won't work 👆For Ruby Native, cloud builds handle everything. I know Expo has something similar with EAS Build. Do you know anyone building mobile exclusively on Linux @joemasilotti

For strictly compiling `eas build` is world-class. For the entire process, consider (still in beta) which can perform development tasks in a sandbox.

Thanks, Evan. I joined the waitlist.

codex makes ios dev feel like web dev. drag, drop, hot reload everything. no more xcode maze

Oh man I’ve been waiting for this moment so long

Wait… does that mean I can then dev and publish from Linux to Apple Store without needing a Mac?

Publish in one shot from any computer with: npx testflight (eas build).

That is flipping sweeeeeet!

Trying to do the same in @t3dotcodes

building directly with the simulator running is such a different experience, you see the thing come to life while you type instead of guessing what it looks like

How do you get the iOS simulator?

This is the way

🫡

I did mine at

what's the setup here? i'm working on monorepo setup and one of my apps is in expo, would love to know if you have link for the setup guide?

Hey, is there anything like that for Claude Code?

Sure

Stop teasing Evan, give it to me

Is that part of Codex?!

How man! Please give access to this

Codex is the most underrated tool out there.

The simulator integration is the key unlock here — most AI coding demos stop at generating code files, but having the agent actually launch the app, see the UI, and iterate based on what's rendered closes the loop in a way that's qualitatively different. The debugging latency between code change and visual feedback is what makes iOS dev painful; removing that friction matters more than the code gen itself.

that's really cool!

Would be cool to have smth similar in @cursor_ai

Would love to do this with Android.

what the feck

Insane, I honestly just run each time lol

Woah this is incredible 🤯

Nice! Refuse the acquisition offer

こんなことできるんだ。

Very cool! Can this be done in Cursor too?

Yeah, my tool makes the simulator available inside the browser. If you have a local browser mcp, then you now have an iOS dev environment

That’s huge, nice work 💪

How are ya’ll activating the remote browser gosh

⌘+shift+B

Bro could you make a tutorial on setting this up? 🔥🔥🔥🔥

Took me a really long time, but I finally got it working!

Building my iPhone app soon too

Nice! Consider using Expo

👍👍

Now I want to build a Codex app on my mobile.🤣

Go for it!

Has to be expo go?

I need this