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Beside your code, Xcode shows a canvas that renders your view live. You see your UI without ever building and launching the full app. 👀

If the canvas is missing, open the Editor menu and turn on Canvas. It appears on the right, next to your Swift code.

A small #Preview block at the bottom of the file tells the canvas what to render. The template adds one for ContentView automatically.

Change your code and the canvas refreshes almost instantly. This live update loop is what makes SwiftUI feel fast and playful. ⚡

Edit the Text view's wording and watch the canvas change as you type. Seeing results immediately makes experimenting safe and fun.

Sometimes the canvas pauses and shows a Resume button. Click it to restart the preview after a change it could not apply live.

The play-style live mode lets you tap and scroll right in the canvas. You can test buttons and gestures without a simulator.

You can point a preview at a specific device, like an iPhone SE. This helps you check how your layout looks on smaller screens.

Add more than one #Preview block to compare states side by side, such as light mode next to dark mode at the same time.

Preview code is for development only. It never ships to users, so feel free to fill previews with fake sample data.

The canvas is far quicker than a full build. Use it as your main loop while designing, and reach for the simulator only for deeper testing.

Which block in your file tells the canvas what to render?

The canvas renders your view live via a #Preview block, updating as you type. It is your fastest way to design and iterate. 🎨