What is Rendering?
Rendering refers to the process by which a browser or search engine processes a webpage’s code (HTML, CSS, JavaScript) to generate the visual content that users see. In the context of SEO, rendering also describes how search engines like Google process a page’s resources in order to understand and index its content.
Rendering occurs after a crawler downloads the page’s content and is necessary for dynamic content loaded via JavaScript to become visible to search engines.
There are three common types of rendering:
- Client-side rendering (CSR): The browser builds the page after downloading and executing JavaScript.
- Server-side rendering (SSR): The HTML is fully generated on the server and sent to the browser.
- Dynamic rendering: Different versions are served to users and crawlers, often using pre-rendered content for bots.
Why Rendering Matters
Many modern websites use JavaScript frameworks that rely on rendering to display important content. If this content is not rendered properly for search engines, it may not be indexed or ranked.
Benefits of optimising for rendering include:
- Ensuring search engines can access key content
- Supporting SEO for JavaScript-based sites
- Improving crawl efficiency
- Reducing rendering-related indexing delays
- Preventing content mismatch between what users and bots see
Search engines may take longer to render JavaScript-heavy pages, so technical optimisation is often needed to avoid missed or delayed indexing.
Example in Use
An online booking site may display available dates using JavaScript. If rendering is not handled properly, search engines might not see those dates, making the page appear incomplete or irrelevant.
Switching from client-side to server-side rendering can help make this content immediately accessible to crawlers.
Related Terms
- JavaScript SEO
- Server-Side Rendering (SSR)
- Client-Side Rendering (CSR)
- Crawling
- Indexing