To make testing more easy easy testing there is a debug option in the back-end. You can enable this in the configuration. It's possible to check test the Href Alternate tags on your pages by enabling this functionallity and simply add ?show-alternate=1 add the end of the url in the frontend.
For example, if your url is:
You need to add it like this:
Now there will be a menu on top of the page where the href-tags tags that are available on this page are shown, so if the product or page is available in the alternative language, the href-tag should be shown here. When it does't show any tags, please make sure that you are using the right targeting settings.
Common mistakes when the href-lang tags are not shown.
The codes are added to the header in Magento. This part of Magento is cached by default, so always flush the cache in Magento after making changes in the configuration.
2) Check the Groups
Check if the shops you would like to link with the alternate tags are placed in the same group, read more about this right here.
3) Unique URLS
Each of the alternate links should be a unique url. When you have the same product on different store views the url's must be unique from eachother so Google can point to that alternate url. Google does not index pages with the language paramater. If you don’t use different domains for different shops you should create unique product url keys or add the store code to the url.
4) CMS Pages
CMS pages should be linked though the newly added category. Please refer to the configuration page.