Whether fastly caching can be avoided in AEM as cloud?

 

In AEM as a Cloud Service, Fastly is deeply integrated into the Adobe-managed infrastructure, and cannot be fully bypassed. However, you can control how and what Fastly caches through HTTP headers and configuration, effectively limiting its behavior for specific scenarios.
 

🔒 Can Fastly Caching Be Fully Avoided?
No, Fastly is not optional in AEM as a Cloud Service—it is part of Adobe's delivery pipeline and is always present in front of AEM Publish tiers. But you can instruct Fastly not to cache certain content.

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✅ How to Prevent or Control Fastly Caching

 
You can minimize or bypass caching by using cache-control headers and related strategies:

1. Use Cache-Control Headers

 
You can configure the response from AEM to include:
Cache-Control: no-store, no-cache, must-revalidate
 

OR 

Cache-Control: private, max-age=0
These headers tell Fastly (and downstream CDNs like Cloudflare) not to cache the content.

2. Set Surrogate-Control Headers

 
Fastly uses Surrogate-Control headers for Varnish-based caching. To explicitly prevent Fastly from caching:
Surrogate-Control: no-store

OR

Header set Surrogate-Control "private, max-age=0, stale-if-error=0, stale-while-revalidate=0"
In the responses, you should see always a MISS for x-cache, as this header is set by Fastly and not Dispatcher. Also, you won't see the Surrogate-Control header passed down.


3. Configure Dispatcher Rules

 
At the AEM Dispatcher level (which also sits behind Fastly), you can specify which paths or file types should not be cached. However, Fastly may still cache unless headers like the ones above are correctly set.

4. Use Headers for Selective Caching

 
You may want to cache only some parts of your site. You can do this by:
•    Setting different cache TTLs (max-age) for different content types.
•    Excluding dynamic or personalized content.

5. Use Query Parameters or File Versioning

 
Ensure dynamic content isn’t cached due to static-looking URLs by using query strings (e.g., ?v=123) or versioned file names.
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🧪 Debugging Fastly Caching

 
You can inspect HTTP response headers to understand Fastly’s behavior. Look for:

•    x-served-by: confirms response from Fastly
•    x-cache: shows HIT or MISS
•    cache-control and surrogate-control: shows cache directives

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Summary
Can Fastly caching be completely disabled?    ❌ No (not in AEM as a Cloud)
Can caching be controlled per-path or content-type?    ✅ Yes
Is Fastly behavior influenced by headers?    ✅ Yes (cache-control, surrogate-control)
Should you rely only on dispatcher rules?    ⚠️ No, headers must align too
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