Describe a time you had to improve the performance of an Angular application.

Structure it as measure, diagnose, fix, verify — and be specific about which kind of slowness it was, because they have different causes.

• Slow initial load usually means bundle size. The tools are source-map-explorer or webpack-bundle-analyzer, and the fixes are lazy-loaded routes, removing a heavy dependency, and setting a budget in angular.json that fails the build when it regresses.
• Slow interaction usually means change detection. Angular Devtools' profiler shows which components are re-checked and how often. The fixes are ChangeDetectionStrategy.OnPush, the trackBy function on ngFor, moving work out of template expressions and getters, and virtual scrolling for long lists.
• Memory growth over time usually means unclosed subscriptions.

Note: The single highest-value detail is that a function or getter called in a template runs on every change detection cycle — sometimes hundreds of times a second. Finding one of those and fixing it makes an excellent, concrete story.