Mobile site and mobile-first indexing best practices

Google uses the mobile version of a site’s content, crawled with the
smartphone agent,
for indexing and ranking. This is called mobile-first indexing.

While it’s not required to have a mobile version of your pages to have your content included
in Google’s Search results, it is very strongly recommended. These best practices apply to
mobile sites in general, and by definition to mobile-first indexing.

To make sure that your users have the best experience, follow the best practices detailed in
this guide.

Create a mobile-friendly site

If you haven’t already, create a mobile-friendly website so your users visiting your site
through a mobile phone can have a stellar experience. There are three configurations you can
choose from to create a mobile-friendly site:

• Responsive design:
  Serves the same HTML code on the same URL regardless of the users’ device (for example,
  desktop, tablet, mobile, non-visual browser), but can display the content differently based
  on the screen size. Google recommends Responsive Web Design because it’s the easiest
  design pattern to implement and maintain.
• Dynamic serving: Uses the same URL regardless of device. This
  configuration relies on
  user-agent sniffing
  and the
  Vary: user-agent HTTP response header
  to serve a different version of the HTML to different devices.
• Separate URLs: Serves different HTML to each device, and on separate URLs.
  Like dynamic serving, this configuration relies on the user-agent and
  Vary HTTP headers to redirect users to the device-appropriate version of the
  site.

The contents of this guide only apply to dynamic serving and separate URL configurations. In
case of responsive design, the content and the metadata are the same on the mobile and desktop
version of the pages.

Make sure that Google can access and render your content

Make sure that Google can access and render your mobile page content and resources.

• Use the same robots meta tags on the mobile and desktop site.
  If you use a different robots meta tag on the mobile site (especially the
  noindex ou nofollow tags), Google may fail to crawl and index your
  page when your site is enabled for mobile-first indexing.
• Don’t lazy-load primary content upon user interaction. Google won’t load
  content that requires user interactions (for example, swiping, clicking, or typing) to load.
  Make sure that Google can see lazy-loaded content.
• Let Google crawl your resources. Some resources have different URLs on the
  mobile site from those on the desktop site. If you want Google to crawl your URLs, make sure
  that you’re not blocking the URL with the
  disallow rule.

Make sure that content is the same on desktop and mobile

Even with the equivalent content, differences in DOM or layout between desktop and mobile page
can result in Google understanding the content differently. However having the same content on
the desktop and mobile version ensures that the two versions can rank for the same keywords.

• 
  Make sure that your mobile site contains the same content as your desktop site.
  
  If your mobile site has less content than your desktop site, consider updating your mobile
  site so that its primary content is equivalent to your desktop site. You can have a
  different design on mobile to maximize user experience (for example, moving content into
  accordions or tabs); just make sure that the content is equivalent to the desktop site,
  since indexing on your site comes from the mobile site.
• 
  Use the same clear and meaningful headings on the mobile site as you do on the
  desktop site.
  

Check your structured data

If you have structured data on your site, make sure that it’s present on both versions of your
site. Here are some specific things to check:

• Make sure that your mobile and desktop sites have the same structured data.
  If you have to prioritize which types you add to your mobile site, start with
  Fil d’Ariane,
  Product, and
  VideoObject
  structured data.
• Use correct URLs in structured data. Make sure that URLs in the structured
  data on the mobile versions are updated to the mobile URLs.
• If you use Data Highlighter, train it on your mobile site. If you use
  Data Highlighter
  to provide structured data, regularly check the
  Data Highlighter dashboard
  for extraction errors.

Put the same metadata on both versions of your site

Make sure that the
title element and
the
meta description are
equivalent across both versions of your site.

Check the placement of your ads

Don’t let ads harm your mobile page ranking. Follow the
Better Ads Standard
when displaying ads on mobile devices. For example, ads at the top of the page can take up too
much room on a mobile device, which is a bad user experience

Check visual content

Check your images

Make sure that the images on your mobile site follow the
image best practices. In particular, we
recommend that you:

• 
  Provide
  high quality images.
  Don’t use images that are too small or have a low resolution on the mobile site.
• 
  Use a
  supported format for images.
  Don’t use unsupported formats or tags. For example, Google supports SVG format
  images, but our systems can’t index a .jpg image in the <image> tag
  inside an inline SVG.
• Don’t use URLs that change every time the page loads for images. Google
  won’t be able to process and index your resources properly if you use constantly-changing
  URLs for them.
• 
  Make sure that the mobile site has the same alt text for images as the desktop site.
  Use
  descriptive alt text
  for images on your mobile site as you do on your desktop site.
• 
  Make sure that the mobile page content quality is as good as the desktop page.
  Use the same
  titles, captions, filenames, and text
  relevant to the images on the mobile site as you do for the desktop site.

Check your videos

Make sure that the videos on your mobile site follow the
video best practices. In particular, we
recommend that you:

• Don’t use URLs that change every time the page loads for your videos.
  Google won’t be able to process and index your resources properly if you use constantly
  changing URLs for them.
• 
  Use a supported format
  for your videos and put videos in supported tags. Videos are identified in the
  page by the presence of an HTML tag, for example: <video>,
  <embed>, or <object>.
• Use the same video structured data on both your mobile site and desktop
  site. For more information, check your structured data.
• 
  Place the video in an easy to find position on the page when viewed on a mobile device.
  For example, it might harm the video’s ranking if users need to scroll down too
  much to find the video on mobile page.

Additional best practices for separate URLs

If your site has separate URLs for the desktop and mobile versions of a page (also known as
m-dot), we recommend the following additional best practices:

• 
  Make sure that the error page status is the same on both the desktop and mobile sites.
  If a page on your desktop site serves normal contents and your mobile site’s
  version of that page serves an error page, this page will be missing from the index.
• Make sure that your mobile version doesn’t have URL fragments. The fragment
  part of the URL is the end of the URL that starts with #. Most of the time,
  URL fragments are not indexable, these pages will be missing from the index after your
  domain is enabled for mobile-first indexing.
• 
  Ensure that the desktop versions that serve different contents have equivalent mobile
  versions.
  If different URLs redirect to the same URL (for example, to the home page on mobile
  devices) after your domain is enabled for mobile-first indexing, all these pages will be
  missing from the index.
• 
  Verify both versions of your site in
  Search Console
  to make sure that you have access to data and messages for both versions. Your
  site may experience a data shift when Google switches to mobile-first indexing for your
  site.

• Check hreflang links on separate URLs. When you use
  rel=hreflang
link elements
  for
  internationalization,
  link between mobile and desktop URLs separately. Your mobile URLs’ hreflang
  must point to mobile URLs, and similarly desktop URL hreflang must point to
  desktop URLs.

  Here’s an example of hreflang for the home page of a site with separate URLs
  for mobile and desktop.

  Mobile

  In this example, the mobile site URL is https://m.example.com/.

  Desktop

  In this example, the desktop site URL is https://example.com/.
• Ensure that your mobile site has enough capacity to handle a potential
  increase in
  crawl rate
  on the mobile version of your site.
• 
  Verify that your
  robots.txt rules
  work as you intend for both versions of your site. The robots.txt file lets you
  specify which parts of a website may be crawled or not. In most cases, use the same
  robots.txt rules for both mobile and desktop versions of your site.

• 
  Use the correct rel=canonical and rel=alternate
link elements
  between your mobile and desktop versions. The desktop URL is always the canonical,
  and the mobile version is the alternate of that URL.

  Here’s an example of rel=canonical and rel=alternate for a
  separate URLs site setup.

  Mobile

  In this example, the mobile site URL is https://m.example.com/ and
  includes a link element that points to the desktop URL as
  the canonical URL.

  Desktop

  In this example, the desktop site URL is https://example.com/ and
  includes a link element that points to itself as the canonical URL,
  followed by another link element that points to the mobile version as the
  alternate version of this URL.

Troubleshooting

Here’s a list of the most common errors that can stop sites from being enabled for
mobile-first indexing or could cause a drop in ranking after a site is enabled for
mobile-first indexing. If your site isn’t enabled for mobile-first indexing yet, you’ve seen a
drop in ranking after your site is enabled for mobile-first indexing, or you’ve received a
message in Search Console, check the following list of common errors and resolve possible
errors you may have: