AWS CloudFront

When someone visits your website from the other side of the world, every request has to travel a long distance to reach your server and the response has to travel the same distance back. That round trip takes time, and on a slow connection or a busy server it adds up fast. AWS CloudFront is Amazon's Content Delivery Network — a CDN — and its job is to reduce that distance by storing copies of your content in locations close to your users.

CloudFront operates through a global network of edge locations. These are data centres spread across dozens of cities worldwide, and they act as caches. When a user requests a file — an image, a JavaScript bundle, an HTML page, a video — CloudFront checks whether that file is already stored at the nearest edge location. If it is, it serves it from there without going near your origin server at all. If it is not, it fetches it from your origin, caches it at the edge, and then serves it. Every subsequent request for the same file from the same region gets the cached copy, fast.

Your origin can be almost anything — an S3 bucket serving static files, an API Gateway endpoint, an Application Load Balancer in front of EC2 instances, a Lambda function URL, or any HTTP server you run yourself. CloudFront sits in front of whatever you have and acts as the entry point for traffic coming from users.

Beyond caching, CloudFront does a few other things that matter in practice. It handles HTTPS termination, meaning it manages SSL certificates for your domain so you do not have to configure TLS on every backend separately. It integrates with AWS WAF for web application firewall rules. And it connects directly to AWS Shield for DDoS protection, which is active by default at the standard tier without any additional configuration on your part.

It is also worth knowing that CloudFront is not just for static content. It is commonly used as a general-purpose reverse proxy, routing different URL paths to different origins — static assets to S3, API requests to Lambda, and so on — all under one domain.

Setting up CloudFront starts in the AWS Management Console. You create what is called a distribution — this is the CloudFront configuration that ties together your origins, your caching rules, your domain settings, and your security options. The setup process walks you through each piece, and for a basic configuration you can have something working in under ten minutes.

The first thing you configure is the origin. This is where CloudFront goes to fetch content it does not have cached. If you are serving a static website from S3, you point the origin at your S3 bucket. If you are running a Lambda-backed API behind API Gateway, you point it at your API Gateway URL. You can have multiple origins in a single distribution and use path-based routing to decide which requests go where — requests to /api/* might go to your API Gateway while everything else goes to S3.

Cache behaviour is the next important configuration area. For each origin or path pattern, you control how long CloudFront keeps content cached, which HTTP methods it forwards, which query strings and headers it passes through to the origin, and whether it compresses responses. Getting caching right matters a lot: cache too aggressively and users see stale content; cache too little and you lose most of the performance benefit and pay for more origin requests.

Custom domains are straightforward with CloudFront. You request an SSL certificate through AWS Certificate Manager — which is free — attach it to your distribution, and add a CNAME record in your DNS pointing your domain to the CloudFront distribution URL. From that point, traffic to your domain goes through CloudFront. If you use Route 53 for DNS, the integration is slightly smoother because you can use an alias record instead of a CNAME, which removes a DNS lookup step.

One CloudFront feature that comes up often in real projects is cache invalidation. When you deploy a new version of your site or update a file, you need to tell CloudFront to stop serving the old cached version. You do this by creating an invalidation — you specify the paths you want to clear, CloudFront removes them from all edge caches within a few minutes, and the next request for those paths fetches a fresh copy from your origin. The first 1,000 invalidation paths per month are free; beyond that there is a small charge per path.

Lambda@Edge and CloudFront Functions are two features worth knowing about even if you do not use them immediately. Both let you run code at the edge — at the CloudFront level — rather than at your origin. This means you can modify request and response headers, redirect URLs, perform lightweight authentication, or rewrite paths without the request ever reaching your backend. CloudFront Functions are simpler and cheaper for small operations; Lambda@Edge supports more complex logic and more AWS integrations but comes at higher cost.

AWS CloudFront Getting Started: https://docs.aws.amazon.com/AmazonCloudFront/latest/DeveloperGuide/GettingStarted.html

CloudFront pricing has several components, and understanding all of them upfront saves you from surprises later. The main charges are for data transferred out to users, HTTP requests processed, and optionally for any Lambda@Edge or CloudFront Functions you run. There is no fixed monthly fee for a CloudFront distribution itself.

Data transfer out is the largest cost for most users. The rate depends on which region your users are in. For traffic served to users in Europe and North America — the two cheapest regions — the price is around $0.085 per GB for the first 10 TB per month, dropping in tiers as volume increases. Traffic to regions like South America, Australia, or India is more expensive, typically $0.16 to $0.25 per GB. If your users are concentrated in one region, you can use CloudFront price classes to limit which edge locations serve your content and reduce cost, at the expense of slightly higher latency for users in excluded regions.

HTTP requests are charged separately from data transfer. HTTPS requests cost around $0.0100 per 10,000 requests, and HTTP requests (unencrypted) are slightly cheaper. For most projects the request cost is a small fraction of the data transfer cost, but for APIs that return small responses — where you have many requests but little data — the request pricing becomes more relevant.

Cache invalidations beyond the free 1,000 paths per month cost $0.005 per path. If you are doing frequent deployments with many invalidations, this adds up, but it is rarely a significant line item compared to data transfer.

The free tier for CloudFront is generous. Each month, for the first twelve months, you get 1 TB of data transfer out and 10 million HTTP and HTTPS requests at no charge. For a personal project or a low-traffic site, this covers everything. After the free tier, costs scale linearly with usage and are broadly predictable once you know your approximate traffic volumes.

One important thing that catches people: data transfer between CloudFront and your origin within AWS — from S3 to CloudFront, for example — is free when both are in the same AWS region. You only pay for data going out to users. This makes the combination of S3 and CloudFront particularly cost-effective for static content, because the bulk of the cost is only the final delivery to end users.

Full pricing details: https://aws.amazon.com/cloudfront/pricing/

CloudFront is one of the most widely used services in the AWS ecosystem, and for good reason. It solves a real problem — delivering content quickly to users who are geographically distant from your servers — and it does so reliably, at a price that scales with actual usage rather than requiring a fixed commitment upfront.

The core concept is simple: content gets cached at edge locations close to your users, so they get fast responses without every request going all the way to your origin. The configuration has more moving parts than some AWS services, but once you understand origins, cache behaviours, and distributions, the rest follows naturally.

For static websites hosted on S3, CloudFront is the standard way to add a custom domain, HTTPS, and global performance in a single step. The combination is reliable, well-documented, and cheap enough that there is almost no reason not to use it. The free tier covers a full year of moderate traffic, and the ongoing costs are predictable.

For dynamic content — APIs, server-rendered pages, real-time data — CloudFront is still valuable as a layer in front of your backend, but caching requires more thought. You need to be intentional about which responses you cache, for how long, and what happens when content changes. Cache invalidation handles the update problem but adds operational overhead if you are doing frequent deployments.

Security is worth mentioning as a standalone benefit. HTTPS is handled at the edge without you needing to manage certificates on your backend servers. DDoS protection through AWS Shield Standard is on by default. Integration with WAF gives you the ability to block malicious traffic before it ever reaches your origin. These are meaningful protections that you get without significant additional configuration.

If you are building anything intended for users in multiple regions — or even if you are building for a single region but want reliable performance and HTTPS without managing a lot of infrastructure — CloudFront belongs in your stack. Start with a simple distribution pointing at an S3 bucket or an existing API endpoint, get comfortable with how caching and invalidations work, and expand from there as your needs grow.