SwiftUI From the Inside. Rebuild it. Measure it. Understand it.

You ship SwiftUI and it works. Then a screen redraws when you did not expect it, or a piece of state resets for no reason you can name.

This book replaces the guessing with measuring. You build a small original version of each idea. Then you run the real SwiftUI on the same question and compare the numbers.

What you will do

Predict which views run again after a change, and prove it with a counter.
See why state follows identity and not position.
Run the layout negotiation by hand, including stacks, priorities and custom layouts.
See what turns into a Core Animation layer, and what a redraw costs.
Build a spring from the physics, and find where it overshoots and settles.

What exists today

Thirteen chapters, a preface and appendices.
Exercises for every chapter, with worked solutions.
A companion Swift package of runnable experiments, and a second package with one runnable sample per chapter.
Tests for the companion code that pass on the machine where the numbers were measured.

The release date is not decided.

Honest limits

The book covers macOS. iOS was not measured.
Every number was measured on one Mac with one system version (macOS 27.0.1, build 26A434). On another version the tests print the difference instead of failing.
The models are working models. They match what was measured. They are not proofs, and the internals of SwiftUI are not published.
It is written for developers who already ship SwiftUI.

If the confirmation mail does not arrive within a few minutes, look in your Junk or Spam folder, especially with an iCloud address.

Read the privacy notice.

No form on your screen? Write to mihaelamj@me.com with the subject “SwiftUI book” and I will reply with a sign-up link.