Definition

Rendering is the stage in Google's pipeline where Googlebot loads a page in a headless version of Chrome and executes its JavaScript, producing the fully built HTML that indexing then reads.

Google Search works in three broad stages — crawling, rendering and indexing. Because many sites build part or all of their content with client-side JavaScript, Google renders pages with a recent version of Chrome so that script-generated content becomes visible to indexing. Google has said rendering can happen soon after crawling or be deferred, and content that only appears after rendering can take longer to be indexed than content already present in the initial HTML.

Examples

• Client-side rendered content

  A single-page app returns an almost-empty `<div id="root">` in its initial HTML and injects the article text with JavaScript. Google only sees that text after the rendering stage runs the script.

• Checking rendered HTML

  A developer uses the URL Inspection tool in Search Console to view the rendered HTML and confirm Googlebot sees the same content a visitor's browser does.

Sources

• Google Search Central — In-depth guide to how Google Search works

Related terms

• Crawling
  The process by which search engines discover and download pages from the web using automated programs called crawlers.
• JavaScript SEO
  The practice of making JavaScript-powered websites crawlable, renderable and indexable by search engines.
• Server-Side Rendering
  A rendering strategy in which the server generates a page's full HTML on each request, rather than leaving the browser to build it with client-side JavaScript.

Where QueryCatch uses this

• SEO Audit
• Page Optimisation