Canonical and hreflang tags serve different purposes in Next.js, particularly when handling multilingual or region-specific content.
Canonical tags: These tags tell search engines which URL is the preferred version of a page when multiple URLs contain similar or duplicate content. This matters even for single-language sites—when different routes lead to the same content, canonical tags guide search engines on which URL to index and rank.
Hreflang tags: These tags specify the language and regional targeting of a webpage. They connect different language versions of the same page, helping search engines show users the right version based on their language and location.
For single-language blog posts available under different routes without duplicate content, hreflang tags aren't necessary. However, canonical tags remain valuable to prevent duplicate content issues when the same content can be accessed through different URLs.
Next.js applications with internationalization (i18n) typically need both canonical and hreflang tags for proper indexing and targeted content delivery. Here are key steps for implementing i18n in Next.js:
Using a dynamic route segment for the locale
Utilizing redirects and rewrites in middleware to direct users based on their preferred language
Setting the language in the root layout