CloudFront is usually added to an architecture with good intentions: performance, reliability, lower origin load.Then, months later, it shows up near the top of the AWS bill — and nobody is sure why.
The uncomfortable truth is that CloudFront rarely becomes expensive because of one big mistake.It becomes expensive because it amplifies small inefficiencies at scale.
Here are the places where CloudFront quietly burns money — and what to look at first.
Caching Is Not a Checkbox
Most CloudFront cost problems start with caching that exists, but isn’t designed.
Different types of content behave very differently, yet they’re often served under the same cache policy. Immutable static assets, frequently changing HTML, and API responses all deserve different treatment.
Files with unique names (especially hashed assets) should be cached aggressively. If the filename changes on every build, the file itself is effectively immutable. Revalidating it every few minutes is pure waste.
At the same time, content like index.html does change — but disabling caching entirely is rarely the right answer. A short TTL is usually enough to balance freshness and cost.
Once CloudFront caching is reasonable, browser caching becomes the next win. Proper Cache-Control headers on S3 objects reduce repeated requests and quietly cut costs without touching infrastructure.
If CloudFront Isn’t the Only Entry Point, You’re Overpaying
When content is downloaded directly from S3 instead of passing through CloudFront, you don’t just lose money — you also lose security.
This usually happens when an application accidentally exposes raw S3 URLs or when old links still point to the bucket. From a user perspective everything still works, but behind the scenes S3 is serving traffic that CloudFront should be handling.
Financially, this bypass means: no caching and compression -> Higher S3 data transfer costs. But the bigger issue is security.
An S3 bucket that’s accessible to the public or reachable directly from the internet is a misconfiguration. In production, S3 should only serve content through CloudFront, enforced by Origin Access Control (OAC).
When OAC is configured, CloudFront becomes the only trusted entry point. Everything else gets blocked.
If users — or bots — can reach S3 directly, you're both overspending and exposing your storage layer to unnecessary risk.
Compression Is Either On — or You’re Paying for Air
Compression issues are easy to miss because they don’t break functionality.
Some clients and third-party tools send headers that explicitly disable compression. If your origin respects those headers, responses are delivered uncompressed, increasing payload size and data transfer cost.
CloudFront can handle compression safely — but only if automatic compression is enabled. This one setting can be the difference between a reasonable bill and a confusing one.
Zombie Distributions Still Cost Real Money
CloudFront distributions tend to accumulate.
Proof-of-concepts, temporary domains, legacy projects — they’re rarely deleted. Even if nobody uses them intentionally, bots often do.
A quick review of distributions and their traffic metrics often reveals “ghost” resources that should have been disabled months ago. Disable first, delete later.
Unused infrastructure that still receives traffic is pure waste.
Global CDN for a Local Product = Wasted Budget
By default, CloudFront serves content from edge locations worldwide.
If your users are primarily in one region, limiting the distribution to an appropriate price class can reduce data transfer costs without affecting real users. Many teams never revisit this setting after initial setup.
Global reach is powerful — but unnecessary reach is expensive.
Security Rules Also Show Up on the Bill
AWS WAF protects CloudFront, but it also evaluates rules on every request.
Over time, rule sets grow. Managed rules are enabled “just in case”, logging is turned on for everything, and requests that should be blocked early continue through the system.
Regular WAF reviews reduce unnecessary processing and lower CloudFront costs at the same time. Security and cost optimization are not opposites here.
Every Extra Kilobyte Is Multiplied by Traffic
Even with perfect caching, CloudFront charges for data transferred.
This is where developers matter most. It’s worth reviewing what the client actually receives, especially on the initial page load. Many applications return configuration data, metadata, or API fields that the frontend no longer uses.
Every extra kilobyte is multiplied by traffic volume. Compression helps, but it doesn’t make unnecessary data free.
Reducing payload size improves performance, lowers CloudFront costs, and reduces origin load — without touching infrastructure.
You Can’t Optimize What You Don’t Monitor
CloudFront rarely becomes expensive overnight. Costs usually drift upward quietly.
Cost anomaly detection, monthly cost reports, and distribution-level monitoring turn CloudFront from a surprise into a controlled system. Without visibility, even good architectures decay.
Final Thought
CloudFront doesn’t waste your money. It accurately bills you for inefficiency.
Every missed cache opportunity, every extra header, every forgotten distribution is multiplied by traffic. Treat CloudFront as a living system — not a one-time setup — and it will stay cheap and predictable.
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