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Rendering methods

Rendering

Also known as: page rendering, rendering SEO

In SEO and web development, rendering is the process in which a browser or crawler turns HTML, CSS, and JavaScript into the finished page a user sees. For search engines, what counts is which content and links are present in the document after rendering. This entry covers the web meaning. In 3D graphics and architecture, rendering means computing an image from a model.

At a glance

Type
processing step that builds the finished page from HTML, CSS and JavaScript
Affects
indexing, link discovery
Google's renderer
headless Chromium (evergreen)
Rendering approaches
CSR, SSR, static rendering, hydration
Docs
Understand the JavaScript SEO basics

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How does Google render a page?

Google processes JavaScript pages in three phases: crawling, rendering, and indexing. After a page is fetched with a 200 status code, it is queued for rendering. Google says a page may stay in this queue for a few seconds, but it can take longer. Rendering is done by a headless, evergreen version of Chromium, which Google keeps up to date.

Content that JavaScript loads only becomes visible to Google in the rendered HTML. Googlebot discovers links only when they are <a> elements with an href attribute. If the original HTML contains a noindex directive, Google may skip rendering altogether, so removing noindex with JavaScript doesn’t work reliably.

From URL to search resultFive stations from left to right: discovery via links and sitemaps, crawling after checking robots.txt, rendering after waiting in the render queue, indexing with duplicate clustering and canonical selection, serving matching results. Links found in the rendered HTML lead back to discovery. Below each station are typical hurdles according to Google.1 · CRAWLING2 · INDEXING3 · SERVINGDiscoverlinks onknown pages,sitemapsCrawlcheck robots.txt,then fetchthe URLRenderrender queueChromium runsthe JavaScriptIndexcluster pages,pick canonical,storeServeresults fromthe index forthe querynew links from the rendered HTMLTYPICAL HURDLES ACCORDING TO GOOGLEno link,no sitemap*server ornetwork errors,robots.txt blocksno 200 statusor noindex: mayskip renderinglow quality,noindex, duplicateof another URLnot relevant,low quality,robots meta ruleSchematic. Google counts discovery and rendering as part of the crawling stage.* An inference, not a Google statement.
Schematic path of a URL through Google Search. Google describes three stages: crawling (including discovery and rendering), indexing and serving search results. Indexing is not guaranteed. Sources: Google Search Central: In-depth guide to how Google Search works; Google Search Central: Understand JavaScript SEO basics.

Types of rendering

The rendering approach determines where the page is assembled:

  • Client-side rendering (CSR): The server sends a mostly empty HTML shell, and JavaScript in the browser builds the content.
  • Server-side rendering (SSR): The server generates complete HTML for each request.
  • Static rendering: The HTML is generated at build time and served as files.
  • Hydration: Server-rendered HTML is made interactive in the browser with JavaScript.

Google still recommends server-side rendering or pre-rendering because it makes pages faster for users and crawlers and because not all bots can run JavaScript. Dynamic rendering, serving a separate pre-rendered version only to bots, is described by Google as “a workaround and not a long-term solution.”

Where the HTML is created: CSR, SSR, SSG and dynamic renderingFour rows show where the content of a page is created. With CSR the server sends an empty HTML shell and JavaScript in the browser builds the content. With SSR the server renders the HTML on every request and hydration makes it interactive in the browser. With SSG the HTML is created at build time. Dynamic rendering serves finished HTML to crawlers and the JavaScript version to users; Google calls this a workaround.SERVERFIRST HTML RESPONSEBROWSERCSRClient-siderenderingsends HTML shelland JavaScript<div id="app">no contentJavaScript buildsthe contentSSRServer-siderenderingrenders HTMLon every requestcontent isin the HTMLhydration makesthe page interactiveSSGstatic renderingprerenderingHTML is builtahead of timecontent isin the HTMLshows HTML at once,hydration optionalDynamicrenderingworkarounddetects crawlers,renders for themcrawlers: HTMLusers: empty shellfor users, JavaScriptbuilds the contentSchematic. Google renders JavaScript in a separate step after crawling.Not all bots run JavaScript.
What matters for crawlers is whether the content is already in the first HTML response. Google recommends server-side rendering or prerendering and calls dynamic rendering a workaround, not a long-term solution. Sources: web.dev: Rendering on the Web; Google Search Central: Understand the JavaScript SEO basics; Google Search Central: Dynamic rendering as a workaround.

Example

An online store builds its product listings with React in the browser. The delivered HTML contains only this:

HTML
<body>
  <div id="root"></div>
  <script src="/app.js"></script>
</body>

Product names, prices, and links to product pages exist only after rendering. If the script fails or robots.txt blocks /app.js, that content is missing for Google. The URL Inspection tool in Search Console shows the rendered HTML, which can be compared with the source code.

Raw HTML and rendered HTML comparedLeft: the raw HTML as the server sends it, with an empty title and an empty div with the ID app. Right: the same document after rendering, where JavaScript has added the title, an H1 and two links. Google only sees this content and these links in the rendered HTML.RAW HTMLserver responseRENDERED HTMLDOM after JavaScriptJavaScript<head><title></title>empty</head><body><div id="app"></div>empty<script src="app.js"></body><head>+<title>Running shoes</title></head><body><div id="app">+<h1>Running shoes</h1>+<a href="/women/">Women</a>+<a href="/men/">Men</a></div><script src="app.js"></body>Schematic example. Anything JavaScript adds only exists in the rendered HTML.
The raw HTML of a JavaScript page lacks the title, heading and links. Google indexes the rendered HTML and parses it for links again. Source: Google Search Central: Understand the JavaScript SEO basics.

Common mistakes

  • JavaScript or CSS files blocked in robots.txt, so the crawler cannot build the page completely.
  • Navigation built with onclick handlers instead of real links.
  • Important content that only loads after scrolling or a click and is therefore missing at render time.

FAQ

What is rendering in simple words? Rendering turns a page’s code into what you see on screen. The rendered page can look very different from the source code the server delivered.

Do AI crawlers render JavaScript? It depends on the bot. Google notes that not all bots can run JavaScript. In our editorial assessment, many AI bot operators do not document whether they render. Content that is already in the delivered HTML is readable for every crawler.

More on the searchVIU blog

Sources

  1. Understand JavaScript SEO basics – Google Search Central (last updated 2026-03-04)developers.google.com
  2. Rendering on the Web – web.devweb.dev
  3. Dynamic rendering as a workaround – Google Search Central (last updated 2025-12-10)developers.google.com
  4. Fix lazy-loaded content – Google Search Centraldevelopers.google.com
  5. Introduction to robots.txt (resource files) – Google Search Centraldevelopers.google.com

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