CloudFront Functions vs Lambda@Edge cost: lightweight vs full compute

Quick answer

CloudFront Functions cost about $0.10 per million invocations for lightweight, sub-millisecond viewer request/response logic. Lambda@Edge bills per request plus compute duration and runs heavier code across all four CloudFront event types. For simple header manipulation, redirects, and URL rewrites, CloudFront Functions are much cheaper; use Lambda@Edge only when you need its power.

CloudFront offers two ways to run code at the edge, and they sit at very different price and capability points. Choosing the lighter one where it suffices, rather than reaching for Lambda@Edge by default, meaningfully cuts edge-compute cost on high-traffic distributions.

Two edge-compute options

	CloudFront Functions	Lambda@Edge
Pricing	~$0.10 / million invocations	Per request + compute duration
Events	Viewer request/response only	All four (viewer + origin, request + response)
Capability	Lightweight JS, sub-ms, no network	Full Node/Python, network access, more compute
Cost at scale	Much lower	Higher

CloudFront Functions run lightweight JavaScript in sub-millisecond time for viewer request and response events, priced simply per invocation. Lambda@Edge runs full functions with network access and more compute, across all four event types, billed per request plus duration like regular Lambda.

Use the lighter tool where it fits

Common edge tasks, header manipulation, simple redirects, URL rewrites, token validation, A/B routing, fit CloudFront Functions, which are dramatically cheaper at high request volume. Lambda@Edge is for tasks that need its power: calling other services, heavier processing, or origin-side events. On a high-traffic distribution, doing simple logic in CloudFront Functions instead of Lambda@Edge is a large saving.

Choosing between them

Default to CloudFront Functions for viewer-side, lightweight logic, and use Lambda@Edge only when you need network access, more compute, or origin events. This is the same match-the-tool discipline as choosing the right compute for a task: the cheaper option is often enough.

FAQ

How do CloudFront Functions and Lambda@Edge differ in cost?

CloudFront Functions cost about $0.10 per million invocations for lightweight viewer logic. Lambda@Edge bills per request plus compute duration, like regular Lambda, and is more expensive. For simple edge tasks at high volume, CloudFront Functions are dramatically cheaper.

When should I use CloudFront Functions?

For lightweight, viewer-side logic: header manipulation, simple redirects, URL rewrites, token validation, and A/B routing. They run sub-millisecond JavaScript at low per-invocation cost, so they are ideal for common edge tasks at high request volume.

When do I need Lambda@Edge instead?

When you need capabilities CloudFront Functions lack: network access to call other services, heavier compute, longer execution, or origin-side events (origin request and response). Lambda@Edge is more powerful and more expensive, so use it only where its capabilities are required.

How do I reduce CloudFront edge-compute cost?

Do lightweight viewer logic in CloudFront Functions rather than Lambda@Edge, since they are much cheaper per invocation. Reserve Lambda@Edge for tasks that genuinely need its power. On high-traffic distributions, moving simple logic to CloudFront Functions is a large saving.

Can CloudFront Functions call other AWS services?

No. CloudFront Functions run lightweight JavaScript with no network access, for sub-millisecond viewer request and response manipulation. If you need to call other services or the network, use Lambda@Edge, which has full compute and network access at higher cost.

Does C3X estimate edge compute cost?

Edge compute cost is driven by invocation volume and, for Lambda@Edge, duration, which are usage inputs tied to request traffic. C3X prices the surrounding CloudFront infrastructure, and you model invocation volume to estimate the edge-function charges.

What to do next

Model your edge compute before you deploy. C3X reads your Terraform and prices CloudFront and the rest of your stack against a live catalog. Start with the quickstart.