What is Browser Caching?
Browser caching is a mechanism where web browsers store copies of static resources like images, CSS, and JavaScript files locally so that subsequent page visits load faster without re-downloading those assets.
How Does Browser Caching Work?
When a user first visits a website, the browser downloads all the resources needed to display the page. With proper caching headers in place, the browser stores these files locally and reuses them on future visits or when navigating to other pages on the same site. This dramatically reduces page load times and decreases the amount of bandwidth consumed by both the server and the visitor.
Website owners control browser caching behavior through HTTP headers such as Cache-Control and Expires, which specify how long each resource should be stored before the browser checks for an updated version. Properly configured caching is one of the simplest and most effective performance optimizations, and tools like Google PageSpeed Insights specifically check for correct caching policies.