Caching in AEM for download speed
When working with Adobe Experience Manager (AEM), a major challenge is ensuring fast content delivery. Poor caching strategies can slow down websites, increase costs, and frustrate users. Here, I’ll share my experience with AEM caching and the solutions that have worked for me and my clients.
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Understanding AEM’s Caching Layers

AEM provides several layers of caching, and using them effectively can drastically improve performance. Here’s a quick breakdown:

– Dispatcher Caching – The first and most important line of defense.
AEM’s Dispatcher is a reverse proxy that caches responses before they reach the AEM backend, reducing unnecessary load on publish instances.

– Sling Resource Caching – Helps store resource resolution mappings in memory to avoid repeated lookups.

– HTL (Sightly) Template Caching – Ensures that server-side rendering of components is efficient and not processed repeatedly.

– Browser Caching – Configuring proper HTTP headers to ensure static assets are cached on the client-side.

– OSGi Service Caching – Storing frequently accessed data within AEM services to minimize API calls and database queries.

– Each of these layers has its own role, but only a well-structured caching strategy brings real benefits.

Common Caching Mistakes and How to Avoid Them

1. Not Using Dispatcher Effectively

Many teams don’t optimize Dispatcher rules, causing unnecessary requests to AEM publish instances. I configure Dispatcher to aggressively cache HTML, JSON, and static assets while allowing selective dynamic content updates.

2. Forgetting Cache Invalidation

Caching is effective—until outdated content is served. I ensure Dispatcher flush rules are properly configured and integrate cache purging into workflows for automatic refreshes with new content updates.

3. Overlooking Component-Level Caching

In complex AEM sites, some components can be cached while others stay dynamic. I use Sling Dynamic Include (SDI) to replace cached fragments with real-time content, ensuring speed without sacrificing personalization.

4. Neglecting Client-Side Caching

Developers often neglect browser caching while focusing on server-side optimizations. By setting proper cache-control headers, I ensure CSS, JS, and images aren’t downloaded repeatedly, significantly reducing load times.

Real-World Performance Gains

One of the biggest transformations I’ve seen was with a client experiencing slow page loads due to high backend traffic. By optimizing caching—Dispatcher rules, SDI for personalization, and browser caching—we reduced backend load by 70% and improved page speed by 50%.

Conclusion

Caching in AEM is not just a technical challenge but a strategic approach. Proper caching results in a faster website, lower server costs, and higher conversion rates. At DevHandler, we tailor solutions to business goals. Contact us with any questions about AEM caching!