Best AI to Build an App: Codex, Claude Code, Cursor

Which AI should you pick to build an app?

If you want to work inside your own mobile project, look at Codex, Claude Code or an editor with an agent like Cursor. If you'd rather start from a description and a generated preview, look at app builder platforms. Either way, check the project format, testing on a phone and the publishing path. Either way, too, we're talking about vibe coding.

The right choice depends on what you want to build and what you're able to check. A tool that can generate a lot of code doesn't guarantee a usable app.

I build my own apps with React Native and Expo. My experience with Claude Code and Cursor shapes the method advice below. The capabilities of the other tools come from their documentation. This guide isn't a benchmark of their quality.

Three ways to work with AI

An agent in your project. It reads files, edits them and can run commands in your environment. You ask for a feature, you review the changes and you test. Codex and Claude Code offer this workflow.

An editor with an agent. You keep a code interface open to follow the files and their diffs. Cursor offers this way of working, with an agent that can act on the project.

An app builder. You describe your idea in a platform that handles part of the creation and the preview. The output format varies: web app, mobile project or Apple-specific project. Check that output before you build your whole product on it.

A regular conversation in ChatGPT or Claude can also help you understand an error and prepare a request. Other modes of these products may have extra access and tools: don't confuse a simple chat with an agent connected to your folder.

Codex: OpenAI's path for working in code

Codex CLI lets you work from the terminal. The official quickstart also covers the desktop, editor and remote surfaces.

To get started, open your app's folder and ask for an explanation of how it's organized before any change. Then give it a small task with an observable result, like adding an item to a list and finding it again after closing the app.

The guide to building an app with Codex walks through this first path.

Claude Code: another agent for the same project

Claude Code can read and edit files, run commands and work across several interfaces. It fits the same principle: one precise task, a limited change and a check.

In my projects, stack rules and product constraints keep the agent from guessing. You still review the plan before a major change, then examine the diffs and the result.

To choose between the two agents, the Codex vs Claude Code comparison offers a shared exercise. To follow the Anthropic path, check out the Claude Code tutorial.

Cursor: following changes in an editor

The Cursor Agent documentation describes how it works on code and its tools. This path might suit you if you want to keep the files in front of you, inspect a diff and tweak a detail.

The editor doesn't replace the method. An interface with lots of panels can take time to learn. Start by finding the project, the terminal and the modified files, then work on one feature at a time.

Lovable, Rork and FlutterFlow: look at the output before the preview

Lovable's FAQ states that the tool produces web apps. A mobile adaptation, a PWA and an app submitted to the store are separate paths.

The Rork Max page presents a SwiftUI path for Apple. FlutterFlow documents an App Store deployment from its visual environment.

To choose among these platforms, see the Lovable, Rork and FlutterFlow comparison. In particular, check the export conditions, the features you need and whether you can take over the project.

Table to choose your first path

Your need	Path to look at	First check
Edit an existing mobile project	Codex or Claude Code	The agent understands the folder and the commands
See and review code in an editor	Cursor with agent	You can find and read a change
Quickly share a service through a link	A web builder like Lovable	The flow works in the phone's browser
Build a mobile app inside a platform	Rork or FlutterFlow	The project can be tested and shipped for your goal
Understand an error or shape an idea	A conversation with AI	The explanation lets you act in your real project

This table points you to a first try. It doesn't rate the tools' quality.

What to check with all these tools

For each feature, ask what was tested and walk through the flow on a device. Agents can use screenshots or rendering tools when they're set up. They don't automatically see your phone.

Also check where the data lives, what happens offline and how to get back to a version that works. For a paid app, purchase and restore need their own tests.

The pitfalls of an AI-built app and the App Store guide cover what comes next.

What budget should you plan?

Check the current plans before paying: interfaces, quotas and credits can change. Compare the cost of the building tool with the product's expenses after launch. An API call in your app can be billed separately from your agent subscription.

The iPhone app budget helps you ask these questions. You can start with one small feature before stacking up services.

Pick a tool and finish a first version

If you're starting out, stick to a single path until you have a feature you can show and test. The iOS Kit gives you the Starter Code from my apps and the Claude Code skills for each step. For the full method with AI, see the vibe coding course page. If your tool is already Claude Code, the Claude Code course page starts from it.

Still torn between two tools? The free diagnostic starts from your situation and the tool you already use, and tells you which step to tackle first. You also get my Apple anti-rejection checklist.

Frequently asked questions

Which AI should I use to build an iPhone app?

Choose based on what you want to build and what you're able to check. To work inside your own mobile project, look at Codex, Claude Code or an editor with an agent like Cursor. To start from a description and a generated preview, look at app builder platforms. Either way, check the project format, testing on a phone and the publishing path.

What's the difference between Codex, Claude Code and Cursor?

Codex and Claude Code are agents that work inside your project. They read files, edit them and can run commands in your environment. You ask for a feature, you review the changes and you test. Cursor is an editor with an agent: you keep a code interface open to follow the files and their diffs.

Can ChatGPT build an app?

A simple conversation with ChatGPT can help you understand an error and prepare a request. It isn't an agent connected to your folder. To work in your code, look at Codex, OpenAI's path: it reads files, edits them and can run commands. Other ChatGPT modes may have extra access and tools.

Can you build an app with AI for free?

It depends on the plan of the tool you choose. Interfaces, quotas and credits can change, so check the current plans before paying. Also compare the cost of the building tool with the product's expenses after launch. An API call in your app can be billed separately from your agent subscription.

How do you build your own app with AI as a beginner?

Pick a single path and stick with it until you have a feature you can show and test. You can choose between an agent in your project, an editor with an agent or an app builder. Start with a small task with an observable result, like adding an item to a list and finding it again after closing the app. For each feature, ask what was tested and walk through the flow on your phone.

Can you publish to the App Store with Lovable, Rork or FlutterFlow?

It depends on the tool, because the output format varies. Lovable builds web apps: a mobile adaptation, a PWA and an app submitted to the store are separate paths. The Rork Max page presents a SwiftUI path for Apple, and FlutterFlow documents an App Store deployment from its visual environment. The Lovable, Rork and FlutterFlow comparison goes through these choices.