Browser Caching

CachingCaching stores previously retrieved content so it is available faster on repeat requests, relieving both servers and the network.Open glossary entry → means storing content temporarily so it does not have to be regenerated or transferred again on each request. With browser caching, the browser stores files such as images, CSSCascading Style Sheets (CSS) is the language used to define the layout and design of web pages. CSS controls colours, fonts, spacing and arrangement, among other things.Open glossary entry → and JavaScript locally, so returning visitors load pages faster. In addition, there is server-side caching such as page cache, object cache or OPcache, as well as edge caching in the content delivery network (CDN)A content delivery network (CDN) is a network of distributed servers that delivers static content closer to the user, reducing loading times.Open glossary entry →.

Caching is an important lever for server response (Time to First ByteTime to First Byte (TTFB) is the time until the browser receives the first byte of the server response, describing how quickly the server reacts.Open glossary entry →, TTFB) and thus indirectly for Largest Contentful Paint (LCP)Largest Contentful Paint (LCP) measures when the largest visible content element in the viewport has loaded, representing the perceived loading speed.Open glossary entry →. Missing caching is a common cause of slow loading times. Typical measures:

• enable server-side page and object caching,
• set caching headers correctly for static assets,
• use edge caching via a CDN,
• configure server-side caching in the CMSA content management system (CMS) is software for creating, managing and publishing web content, usually without programming knowledge. Well-known examples are WordPress or Shopify.Open glossary entry →, for example WordPress.

A good PageSpeed check therefore also verifies whether caching is active and sensibly configured.