Drupal Page Cache Overview Examines Performance for Anonymous Traffic

Caching is the focus of a new Drupal explainer by Saroj, examining how Page Cache stores fully rendered HTML responses and serves them directly to anonymous users on repeat requests. The article describes Page Cache as one of Drupal Core’s primary performance optimisation layers because it reduces repeated Drupal bootstrapping, database queries and render array generation.

Published on Weekly Drupal, the explainer outlines how Page Cache operates alongside cache tags, cache contexts and max-age metadata while integrating with infrastructure components such as Redis, Varnish, CloudFront and Akamai. The article notes that Page Cache primarily benefits anonymous visitors, while authenticated users generally rely on Dynamic Page Cache. 

The post also examines operational considerations surrounding Drupal caching infrastructure. These include HTTP response headers such as X-Drupal-Cache: HIT, CDN invalidation workflows during deployments, cache warming practices and API response caching patterns used in headless Drupal architectures.

A production example included in the article describes a federal Drupal deployment where cached homepage delivery reportedly reduced page load times from 1.8 seconds to 150 milliseconds during periods of heavy traffic. The article does not independently verify the benchmark figures or provide detailed implementation metrics.

The explainer concludes with a review of common production issues including uncacheable blocks, cookie-triggered CDN bypass behaviour, low cache max-age settings and stale content caused by missing cache tags. It also briefly references emerging AI-assisted cache optimisation approaches such as predictive cache warming and traffic-based TTL adjustment.