# HTTP Link header

Category: [Technical SEO](https://seo-geo-glossary.com/en/glossary/category/technical-seo/) › [Servers, HTTP & caching](https://seo-geo-glossary.com/en/glossary/category/technical-seo/servers-http-caching/) · Also known as: Link header

The **HTTP Link header** is a response header that expresses links between resources, with the same meaning as the HTML `<link>` element. RFC 8288 defines it.

## What is the Link header used for?
Each entry holds a target URI in angle brackets plus parameters, of which `rel` (the relation type) is required. MDN describes common uses such as `preload` and `preconnect`, which let the browser start fetching before it has parsed the HTML, and `prev`/`next` for paginated APIs.

For SEO, the most relevant use is `rel="canonical"`. Google's documentation states that a `rel="canonical"` HTTP header can tell Googlebot the canonical URL for non-HTML files such as PDFs, and that Google supports this method for web search only.

## Example
```http
Link: <https://www.example.com/downloads/white-paper.pdf>; rel="canonical"
```

```http
Link: </style.css>; rel=preload; as=style
```

## Common mistakes
The header is set on the wrong URL, or several Link headers contradict each other. Because the header is not visible in the page source, it is easy to overlook in audits.

## Related terms

- [HTTP header](https://seo-geo-glossary.com/en/glossary/http-header/index.md)
- [HTTP status code](https://seo-geo-glossary.com/en/glossary/http-status-code/index.md)
- [Canonical tag](https://seo-geo-glossary.com/en/glossary/canonical-tag/index.md)
- [Preload / preconnect](https://seo-geo-glossary.com/en/glossary/preload-preconnect/index.md)

## Sources

- [RFC 8288: Web Linking](https://www.rfc-editor.org/rfc/rfc8288.html)
- [Link header – MDN](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Link)
- [Consolidate duplicate URLs, rel=canonical HTTP header – Google Search Central](https://developers.google.com/search/docs/crawling-indexing/consolidate-duplicate-urls#rel-canonical-header-method)

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Last updated: October 7, 2026
URL: https://seo-geo-glossary.com/en/glossary/http-link-header/