Rendering is what happens when a search engine web crawler visits a web page, runs the code on the page, and turns that code into an interactive web page. In other words, it’s how Google and other search engines digest your content. This article provides some of the most interesting insights from our recent webinar, Practical Rendering SEO Explained.
The first noted mentions of rendering in any Google documents stretch back to various Google patents in 2011. One example is “Page rendering for dynamic web pages”. The majority of Google patents on the topic of rendering have a strong focus on page layout. One of Google’s patents on rendering spells out the importance of content location on the page as follows:
“Text appearing above the fold (visible without scrolling) is may be considered more important than the text below the line”
So, why do rendering and page layout actually matter? The answer is that if your pages aren’t rendered correctly or completely, some parts of those pages won’t be indexed.
There are four shades of any website that lead to differences in how pages look:
How a website’s code is rendered on an end user’s device determines which of these shades of your website they interact with. In terms of rendering’s impact on ranking, if something breaks your rendering and the content doesn’t display properly, Google can’t see it. And, if Google can’t see your content, they can’t index and rank it.
New URLs come online all the time. Due to bandwidth constraints on the Internet, Google can’t crawl all of these URLs at the same time. Web page URLs enter a queue, and there’s a lag time between when Google discovers a URL to when it crawls. And for pages that have already been crawled, there’s a lag time between when Google bots crawl those pages again.
After a crawl completes, Google can look into the HTML found on the page and its HTTP status. If there are errors, such as a 404, the processing ends there. If there’s a robots.txt meta tag that says noindex, which instructs Google not to index that particular page, the processing also ends here.
If there’s HTML content found, the page then enters another queue for JavaScript execution. Pages are then indexed in Google’s search results, and a range of other factors, such as content quality, backlinks, etc determine how well the page ranks in those search results.
When a search engine bot crawls a website, you can think of this initial step as grabbing a recipe (web page) from a really big cookbook (URLs on the Internet).
Think of the HTML on a page as a recipe. This recipe contains a bunch of code, which are instructions on how to make the page. This code contains CSS elements, JavaScript, videos, text, images, headings, and other page “ingredients”.
The web page that users see in their browser is the final dish. The rendering process is akin to the cooking and preparing of that final dish, and Google is the chef. In technical terms, rendering parses the HTML on a page to turn it from mere text into the visual representation of that page that users can interact with in a web browser.
Rendering is resource-intensive both from the perspective of Google and from the perspective of the end devices that load your website’s pages. Sometimes, the rendering process doesn’t work optimally.
For example, if your pages are very dynamic and JavaScript-heavy, this can slow down the rendering process. You might see that your competitors’ new pages are being indexed within 24 hours but it takes your page a week or two to get indexed. From a user experience perspective, more ‘expensive’ pages take longer to load and render on their devices.
Sites could also have content that’s visible on desktop and not on mobile or vice versa. This can happen quite often on eCommerce stores. The problem here is not with the rendering process per se but with displaying different content on different devices.
The value of website builders and platforms such as Duda for the rendering process is that users who run their websites on those platforms benefit from any optimizations made by the platform vendor. If you build your own site and infrastructure, you need to do the optimizations yourself, which can get technically tricky in terms of optimized rendering.
