---
title: seo/canonical-url ยท Canonical URL
description: Every route should include a tag.
---
**Severity:** warning
## What it checks
Every route should include a `` tag (own or inherited through the layout chain). A missing or empty canonical link is flagged.
## Why it matters
A canonical URL tells search engines which URL is authoritative, preventing duplicate-content dilution across query-string variants of the same page. (SvelteKit normalizes trailing slashes itself by default, so that particular variant isn't a concern here.)
## How to fix
Add `` in ``, or set the canonical prop on your meta component:
```svelte
```
## Mode differences
**Source analysis** (the CLI, the dashboard's static baseline) composes each route's `` from `` in the page and its layout chain, followed into repo-local components, plus the known meta components (`svelte-meta-tags`, `svelte-seo`) and any you declare in `metaComponents`. A value it cannot read literally (`{data.title}`) is `dynamic`, judged by `treatDynamicAs`. **Rendered analysis** (the Vite plugin's build pass, a route you visit in the dashboard) reads the shipped ``, where every value is literal and `treatDynamicAs` does not apply; the build pass covers prerendered routes only. When the two disagree, trust the rendered result.
## Disabling
Record existing findings in the suppressions file (`npx svelte-vitals --update-suppressions`), scope the rule per route or path with `overrides`, or turn it off:
```js svelte-vitals.config.js
export default {
rules: {
'seo/canonical-url': 'off'
}
};
```