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But first - a disclaimer. PWA is a standard started and promoted by Google, and while there is no evidence that it is a ranking factor, it definitely shouldn't be neglected. Why? Users' attention is at stake. Google can't allow them to favour native apps over traditional websites even though promoting PWAs may, at some point, cannibalize Google Play. Since most of Google's revenues come from ads in Google Search, not Google Play, Google needs to hold on to the advantage in Search by all means. It is the foundation of its market position.
John Mueller, senior Webmaster Trends Analyst from Google, claimed there are some JS-powered sites on which Googlebot will be able to handle client-side JS. Yet, using the word "some" was a strong suggestion that there were also some problems with it.
Webmaster Central Blog contains a more direct suggestion:
JS parse times on mobile can be even 36% longer than on desktop. The size of JS scripts, code quality, and complexity can significantly affect battery life, especially on low-end devices. Longer JS execution times forced on the user's device delay the first paint of the "hero" content that the user sees on the screen. All of these negatively influence metrics such as Time to First Paint, and First Contentful Paint, which measure how fast content is served to users. The Page Speed is a direct ranking factor, but also has an indirect influence on the SEPRs, by increasing the bounce rate and reducing dwell time.
It is, however, hardly an unambiguous tip, and quite a challenge for businesses. The chances of being clicked are lower when the site gets farther off from the first place rank.
As Carolanne Mangles in Smart Insight, stated:
Click-through rates do, in fact, decline the further down SERPs the result is positioned. Not only do they decline, but the difference between the 1st and 5th position is the largest decrease with an average of 25%. (...) There is a big difference in CTRs for the 1st and 5th place. Users are less likely to scroll down for information as this requires more time - often, the first couple of results are well trusted because Google has placed them higher than results that can be found on page 3.
One of the essential advantages of PWAs is their discoverability. However, PWAs themselves don't win top results in SERPs. To be sure that these JS-based entities are indeed discoverable by users, they need to meet some requirements.
However, due to their JS-reliant nature, they can cause some SEO challenges. It is, undoubtedly, bad news. The good news is, however, the challenges concern Single Page Apps in general, and so SEO optimization of PWAs is possible when it follows the basic SEO practices.
PWAs, in spite of their JS-nature, meet some of these restrictions by default. They are fast, engaging, extremely lightweight, and reliable. However, their SEO-friendliness must be double-checked manually and through SEO tools that crawl the site with and without JS rendering to identify possible gaps. Successful verification solely by Lighthouse might not be enough to take the first place in SERPs. Aleyda Solis, SEO consultant, pointed out, in her blog, that:
The impact of a JS reliant implementation along Google's two indexing waves would likely not be the same. (...) We should validate for ourselves in each case to see up to which point the type of PWA implementation is negatively affecting the site searchability while avoid overlooking "typical" SEO best practices.
Find out how to optimize your JS-based Progressive Web App in SEO for PWA whitepaper 📕
Google does not see user-like interactions such as clicking and scrolling, and so the content or links loaded only upon JS events are invisible to the crawlers. To make the hyperlinks visible to search crawlers, the developers have to use standard HTML < a href=”” > tags.
Each site must have a unique URL address so that the browser could have access to it. Deep linking from your homepage to products or categories also allows Googlebot to crawl the content efficiently.
Use the HTML tag < img src=”” >. It allows loading various image resolutions based on the size of the end device. However, the images served by the server should not be bigger than the resolutions the screen can display. If images are lazy-loaded, they should be marked with tags or structural data so that Googlebot can discover them.
According to many tests, Google waits no longer than 5 seconds for static files to download, and many asynchronous JS-based sites fail to render so fast.
A significant benefit of Progressive Web Apps is the fact that they speed up the process of the application being indexed. Service worker scripts work separately from websites which enables pages to only request raw data and not styling or layout information. Search engines like smooth, fast apps with limited retention, and reward them with higher visibility.
The higher the position in SERPs, the bigger the chance of winning the user's attention.
The #1 result in Google's organic search results has an average CTR of 31.7%. On average, moving up one spot in the search results will increase CTR by 30.8%. source
Besides, the page speed influences the bounce rate, and this metric that describes user engagement also has an impact on how Google measures the page value.
Not to mention that they have an impact on business effects. User engagement, as part of the customer lifecycle, with a well thought out marketing strategy, can lead to increased conversion rates, retention, and —over the long-term— increased loyalty.
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