Mobile SEO

How relevant are websites optimised for mobile devices?

Out and about with a smartphone always at hand – that's everyday life today. As early as 2015, more Google searches were made on mobile devices than on desktop computers for the first time, and the trend has grown stronger since. In e-commerce, most visits now take place on mobile. Mobile SEO is therefore no longer an add-on discipline but a basic requirement. What should a mobile website look like, and what needs to be considered for search engine optimisation?

Google's “mobile first” approach: why mobile SEO is one of the basics

Google has gradually switched its indexing to “mobile first”: since 2023, practically all websites have been crawled with the smartphone crawler, and since July 2024, Google no longer crawls websites that are not accessible on mobile devices at all. For rankings, it's the mobile version of a page that counts – Google doesn't take into account content that is only visible on desktop. For site owners, this means:

• The website must be fully usable on smartphones

• Mobile and desktop versions should contain the same content, structured data and meta information

Mobile-first indexing relates to content: what isn't displayed on the smartphone may well not exist for Google. Then there's user experience: loading time, usability and stable display (Core Web Vitals) feed into the evaluation. What does this mean in concrete terms for website and shop owners?

How does mobile SEO differ from regular SEO?

Mobile users often have different needs: they want specific information quickly, easy one-thumb operation and a smooth checkout. Separate content for mobile devices isn't necessary for this, however – on the contrary: Google explicitly recommends offering the same content on all devices and only adapting the presentation.

Local relevance is one example: someone searching at home for a restaurant for next weekend wants to see photos, the menu and reviews. Someone who gets hungry spontaneously in town mainly wants to know on their smartphone which restaurants are nearby, whether they are open and how they are rated. A good mobile page offers both, but puts the most important information and actions – opening hours, call, directions – right at hand.

Options for implementing a mobile website

There are various options for making your site and its layout fit for mobile SEO:

• Responsive design

• Dynamic serving

• Separate mobile website

Responsive design

Responsive design means that elements and page structure automatically adapt to the screen size. All devices get the same URL and the same HTML code; only the presentation changes via CSS. This is the solution recommended by Google and is standard in modern shop systems such as Shopware and Shopify today. It's important that no content disappears on small screens, nothing is distorted and navigation, filters and checkout remain easy to use. A poor mobile user experience costs conversions – a good one reduces bounces and strengthens the signals Google evaluates.

Advantages

• Recommended by Google

• One URL and one system, no separate page versions

• Independent of the device

Disadvantages

• Requires careful implementation so that complex pages remain fast and clear on mobile too

Dynamic serving

With dynamic serving, the server delivers different HTML code under the same URL depending on the device. The server recognises the device by its user agent and outputs the appropriate version. For Google to capture both versions correctly, the server must send the HTTP header “Vary: User-Agent”. Google supports the method but tends to advise against it because it is error-prone.

Advantages

• Presentation can be optimised specifically for individual device types

• Same URL for all devices

Disadvantages

• Error-prone if devices are recognised incorrectly

• Must be adjusted continuously for new devices and browsers

Separate mobile website

A separate mobile website runs under its own address, usually a subdomain such as “m.example.com”. This model was common before responsive design became widespread but is considered outdated today. It means double maintenance and increases the risk of mobile and desktop versions diverging – which can directly cost rankings with mobile-first indexing.

Advantages

• Clear separation of versions

• Rarely useful any more

Disadvantages

• Double maintenance; requires correct linking via canonical and “alternate” annotations, otherwise there is a risk of duplicate content

The same content on all devices?

Yes – that's crucial for Google today. Mobile and desktop versions should contain the same texts, images, headings, structured data and meta information. Content may be displayed in a space-saving way on smartphones, for example in expandable sections; Google still takes it into account. What changes is search behaviour: mobile queries are often shorter, more often have a local reference or are phrased as questions via voice search. Content that clearly answers typical who/what/where questions therefore has an advantage on mobile too.

Mobile content is also frequently shared via messengers and social networks. According to Google, social signals such as likes and shares are not a direct ranking factor, but they do bring visitors and attention.

Special case: app

Instead of or in addition to a mobile website, an app can make sense – for example if customers return frequently, features such as push notifications, customer accounts or loyalty programmes are important, or data should be available offline. However, an app is costly to develop and maintain and doesn't replace the mobile website, as new customers mostly come via search. Apps hardly play a role in Google Search; what matters for them is findability in the app store, so-called app store optimisation (ASO). An intermediate solution is progressive web apps (PWAs), which run in the browser but behave like an app.

What needs to be optimised for mobile SEO

Once the website configuration is in place, it's time to tackle the individual technical levers that matter for mobile SEO. Usability must always be put to the test.

Check loading times and performance

If a mobile page loads too slowly, visitors leave before they see the content. Loading time is therefore particularly decisive on mobile; Google measures it via the Core Web Vitals. Important measures for mobile SEO:

• Avoid large files

• Reduce unnecessary JavaScript, load scripts with a delay

• Smaller and fewer images

• Serve images in modern formats (WebP, AVIF) and the right size

• Load visible content first

• Enable caching

• Avoid redirect chains

Loading time and Core Web Vitals can be checked with Google PageSpeed Insights and in the Core Web Vitals report in Google Search Console.

Optimise the display area of a mobile website

The page width must adapt to the screen size so that content is fully visible without horizontal scrolling. The basis for this is the viewport meta tag in the HTML code. Tables, wide images or product comparisons should be displayed on smartphones in a way that keeps them readable.

Better usability

Usability is particularly important on mobile. Basic measures include:

• Clear arrangement and structuring of page elements

• Short click paths – especially to the cart and through checkout

• No intrusive pop-ups and interstitials that cover the content

• Sufficiently large buttons with enough spacing so they are easy to tap with a finger

• Easily accessible search function, ideally with suggestions while typing

• Easy-to-read font (Google recommends a base font size of 16 pixels) with sufficient contrast

• Mobile-friendly payment methods such as Apple Pay, Google Pay or PayPal

Mobile SEO and local SEO

Local SEO is a form of search engine optimisation that makes businesses visible for search queries with a local reference. Because many of these searches take place on smartphones on the go, mobile SEO and local SEO are closely linked. In addition to the general ranking factors, further criteria apply here:

• Keywords with a local reference (example: ophthalmologist Heilbronn), also in the page title and meta description

• A fully maintained Google Business Profile with address, opening hours and categories

• Reviews: number, average and recency influence local visibility

• Backlinks from local websites, for example regional media, clubs or partners

• Local reference in content, e.g. location pages with individual content

Local and mobile SEO combined

Anyone who takes mobile search seriously should also consider local search: on the go, it's handy to see immediately what's available nearby. Artificial intelligence is expanding these possibilities further. With Google Lens, users can take a photo and see where this or similar products are available; adding a text query helps find matching items – such as clothing in a matching colour to a particular piece. This makes good product images and complete product data a ranking factor on mobile too for online shops.

Conclusion: don't forget mobile SEO

Most online activity now takes place on smartphones. The question is therefore no longer whether a shop needs to be optimised for mobile, but how well it is. Anyone planning a new shop should rely on responsive design, fast loading times and a mobile-optimised checkout right from the start of shop development. We'll also be happy to support you with mobile SEO and local search.