Hydration
Hydration attaches JavaScript interactivity to HTML already rendered by the server: the page displays first, then becomes interactive. When poorly controlled, it freezes the interface for hundreds of milliseconds.
In practice
The classic symptom: a visible page that ignores clicks — INP records it. The remedies: less bundled JavaScript, partial hydration of only the interactive components, deferred loading of non-essential code. Our templates isolate interactive islands; text never needs to wait for a script.