The official routing library is [SvelteKit](https://kit.svelte.dev/), which is currently in beta. SvelteKit provides a filesystem router, server-side rendering (SSR), and hot module reloading (HMR) in one easy-to-use package. It shares similarities with Next.js for React.
However, you can use any router lib you want. A lot of people use [page.js](https://github.com/visionmedia/page.js). There's also [navaid](https://github.com/lukeed/navaid), which is very similar.
If you prefer a declarative HTML approach, there's [svelte-routing](https://github.com/EmilTholin/svelte-routing).
If you need hash-based routing on the client side, check out [svelte-spa-router](https://github.com/ItalyPaleAle/svelte-spa-router), or [abstract-state-router](https://github.com/TehShrike/abstract-state-router/), a mature router for business software.
For filesystem-based routing, you can take a look at [Routify](https://routify.dev).
