# What is a canonical URL

## What is a canonical URL

Canonical url is the url that represents a specific page.

It is obtained in the following order. (This logic is only for Channel.io)

1. Get `href` property of `link` tag `rel` value is canonical

``````<link rel="canonical" href="{canonicalUrl}" />
``````
2. Else, use `url`

Check your web pages' canonical urls!

## Why we use canonical URL

Canonical URL is good for statistics

Here are two urls.

Are these two urls the same page? or not?

Some case is same page, but some case is maybe other page.

So we recognize these urls are different pages.

BUT, if canonical URLs are same, we know these pages are same!

This is the reason why we use canonical URL!

## When we use canonical URL

We use canonical URL as default page for plugin.

Page is important data for viewing a specific support bot.

In order to use the Support Bot well, the canonical url must be set well.

See more about What is page?.

It is also included in the event properties.

## Limitation

Canonical URL is usually not strictly applied.

It is important to apply it correctly so that it can represent some pages.

If all pages have the same canonical url, then we recognize all pages as one.