Product notes
How we design Stress HRV—needs, trade-offs, and gentle answers. Not a marketing changelog.
iOS resizability, explained: when your app stops knowing what device it is on
Five design principles, each landed in code: in the era of window resizing, an app only cares how much space it has. Scene setup, geometry callbacks, two-tier strategy, Info.plist red lines, and a test matrix.
Read noteDesigning for iPhone Duo, from layout to code
Twelve chapters, with SwiftUI and UIKit for the same situation. Learn one checkable judgment at a time, then see why the tabs stay at the bottom.
Read noteApple Watch Recovery HRV: Series 12 & Ultra 4 for Stress
Apple's new Health Sensing System samples HRV up to 24x more often. Here's what Recovery HRV actually tells you about stress and recovery — and where a dedicated stress app fits in.
Read noteYour Normal Isn't the Population Average
The population average is an average computed without you in it. A personal baseline is a ruler written by your own recent weeks — blunt at first, sharper the longer you use it.
Read noteStress alerts should only tell you what actually changed
Smart adapts to how your Watch normally samples. Low-frequency updates still speak individually; only high-frequency bursts are grouped and confirmed more carefully.
Read note
Try these ideas in Stress HRV
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