My API Responded in 4 ms, but Navigation Still Felt Slow (opens in new tab)

I was debugging an internal project management application built with SvelteKit and a Rust API. Locally, navigation felt almost instant. On the VPS, opening the Tickets, Timeline, and OpenSpec docs pages felt noticeably slower. Clicking a ticket also took too long before the preview panel became useful. My first assumption was infrastructure: Maybe the VPS was underpowered. Maybe PostgreSQL queries were slow. Maybe the reverse proxy added latency. Maybe SvelteKit SSR was taking too long. The ...