Islands Architecture

Traditional single-page applications hydrate the entire page on load, even sections that never change. Islands ArchitectureIslands ArchitectureIslands Architecture is a web architecture pattern where most of the page is static HTML and only specific interactive components ( flips that: the page is rendered to static HTML, and only the components that need interactivity (a search bar, a cart, a form) hydrate independently.

The result is dramatically smaller JavaScript payloads, faster Largest Contentful Paint scores, and better Core Web VitalsCore Web VitalsCore Web Vitals are a set of specific factors that Google considers important in a webpage — which is why frameworks like Astro have made islands their default model.