Why Are My Files Still Being Requested After Setting Cache-Control with CloudFront?

Question

Hi everyone,

I'm currently hosting static files on S3 and delivering them through CloudFront. My goal is to reduce request costs by leveraging caching.

I’ve set the following Cache-Control header on the files:

`Cache-Control: public, max-age=31536000, immutable`

I’m also using versioned filenames like app.v1.js, so theoretically, CloudFront should cache the file for up to a year and avoid repeated requests — as long as the content hasn’t changed.

However, I'm still seeing consistent requests to the same files in the CloudFront reports. The data transfer is minimal, but the request count remains high, which doesn't align with what I expected.

I’d like to ask:

Am I missing something in my setup? ( or related our cdn choose 'Legacy cache settings')
Note from here : https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/header-caching.html
For legacy cache settings – If you configure CloudFront to forward all headers to your origin, CloudFront doesn't cache the objects associated with this cache behavior. Instead, it sends every request to the origin.

Does immutable and max-age only affect browser caching and not CloudFront?

Is there a recommended way to truly reduce request counts on CloudFront for static, versioned assets?

Appreciate any help or insights!
![Enter image description here](/media/postImages/original/IMGQ0NIm-RTrOjA-hNhzjyiA)

re:Post Agent · Answer

Your observation about consistent requests to the same files despite setting Cache-Control headers is a common issue, and there are a few factors to consider:

1. Cache-Control headers primarily affect browser caching, not CloudFront caching. While they can influence CloudFront's behavior, they don't directly control it. CloudFront's caching is primarily determined by its own cache settings.

2. CloudFront's caching behavior is controlled by the cache policy you've set up. Even if you've set a long max-age in your Cache-Control header, if your CloudFront distribution's Minimum TTL, Maximum TTL, and Default TTL are set to lower values, CloudFront may still request the file from the origin more frequently.

3. The high request count you're seeing could be due to request collapsing. When CloudFront receives multiple requests for the same object that isn't in its cache, it forwards only one request to the origin and serves the same response to all requesters. This can lead to a high request count in CloudFront reports even though fewer requests are actually sent to your origin.

4. Different edge locations might cache the content independently, leading to more requests than expected if your content is being accessed from various geographical locations.

To truly reduce request counts for static, versioned assets:

1. Review and adjust your CloudFront cache policy. Ensure that the TTL settings (Minimum, Maximum, and Default) are set to appropriate values for your use case.

2. Consider using a managed cache policy like CachingOptimized, which is designed to maximize the cache hit ratio.

3. Verify that your cache key includes only necessary elements. Including too many elements (like unnecessary headers or query strings) can lead to unique cache entries and more origin requests.

4. Use CloudFront's logging features to gain more insight into the caching behavior and identify the root cause of the frequent requests.

5. If you want to ensure that CloudFront respects your origin's cache headers, you can set the Minimum TTL to 0 in your cache policy. This allows CloudFront to use the Cache-Control headers from your origin to determine caching behavior.

Remember, while reducing request count is important, it's also crucial to balance this with ensuring your content stays up-to-date. Make sure your caching strategy aligns with your content update frequency and your users' needs for fresh content.  
**Sources**  
[Cloudfront caching issue | AWS re:Post](https://repost.aws/questions/QUlbDjrF-rTka5Gz2xm29M8w/cloudfront-caching-issue)  
[Add or remove HTTP headers in CloudFront responses with a policy - Amazon CloudFront](https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/modifying-response-headers.html)  
[Disable CloudFront caching question. | AWS re:Post](https://repost.aws/questions/QUv2pYrdd3SV-vO6DccUisUQ/disable-cloudfront-caching-question)  
[Request and response behavior for Amazon S3 origins - Amazon CloudFront](https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/RequestAndResponseBehaviorS3Origin.html)

Why Are My Files Still Being Requested After Setting Cache-Control with CloudFront?

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