The north star is simple: time from npm create proto@latest to a working prototype running in the iOS Simulator — under 60 seconds.

You need two things installed once before that command works. Both are free. Both are macOS-only.

Step 1 — Install Node.js

Node.js 18 or newer is the only prerequisite. Download the LTS version from nodejs.org and install it.

Download Node.js → 

You’ll know it worked when you can open Terminal and type:

node --version

If you see a version number, you’re done.

Step 2 — Install Xcode

Xcode is Apple’s developer tool. Prototo uses its iOS Simulator — the iPhone preview that runs on your Mac. You never need to open Xcode itself. Just install it.

Download Xcode free from the Mac App Store:

Download Xcode → 

After installing, open Terminal and run this once:

xcode-select --install

This installs the command line tools Xcode needs to run the Simulator.

Step 3: Install a coding agent

Your coding agent turns plain language into working screens. Prototo works with two: Claude Code (recommended) and OpenAI Codex. Pick whichever you already pay for. Prototo runs on the AI subscription you already have and never charges for AI use.

Claude Code (from Anthropic):

npm install -g @anthropic-ai/claude-code

You’ll need an Anthropic account. Sign up at claude.ai  if you don’t have one.

Codex (from OpenAI):

npm install -g @openai/codex

You’ll need a ChatGPT account. Sign up at chatgpt.com  if you don’t have one.

Already using Prototo Desktop? It walks you through this choice on first launch, so you can skip ahead.

Using Claude Code? See Configure Claude Code for optional extras.

Step 4 — Create your first Proto project

Once the above are done:

npm create proto@latest myapp

Proto scaffolds the project, installs dependencies silently, and opens the iOS Simulator. You’ll see the starter screen.

That’s it. You’re ready.