AWS has introduced AWS Lambda Web Functions, a new deployment model that allows developers to run standard HTTP web applications on the Lambda platform without rewriting their code into event handlers. This release enables teams to deploy existing port-listening servers built with frameworks such as Express, Hono, Fastify, or Next.js using a single command.
The new form factor operates alongside the existing Lambda Event Functions and Lambda MicroVMs. While Event Functions use an event-driven model with wall-clock billing, Web Functions utilize an HTTP-native model with multi-concurrent execution and active CPU billing. This distinction allows developers to choose the programming model that best fits their workload, whether that is asynchronous backend processing or interactive user-facing APIs.
HTTP-Native Execution and Billing
Web Functions are designed for workloads that handle multiple concurrent requests and I/O-heavy processing. Each execution environment can handle up to 128 concurrent requests, allowing a burst of traffic to share warm environments rather than mapping every request to a new instance. This architecture is particularly useful for server-side rendering, API backends, and AI inference endpoints that stream token responses.
Billing for Web Functions is based on active CPU time. Time spent waiting for database queries or external API calls consumes minimal CPU, which can reduce costs for I/O-heavy web workloads compared to traditional wall-clock billing. Memory usage is metered for the duration the execution environment remains active.
Deployment is streamlined through the AWS Command Line Interface. A single deploy command bundles the source code, creates the Web Function, publishes the first revision, and attaches a Web Function endpoint. The process returns a live HTTPS URL in under a minute. Revisions act as immutable snapshots of the code, while endpoints route traffic to specific revisions or split traffic across them for gradual rollouts.
Global Distribution and CloudFront Integration
The service supports automatic multi-region distribution. Developers can deploy their application to multiple regions, and Lambda configures latency-based routing to direct requests to the region with the lowest latency for the caller. This is managed through a single global URL, simplifying the setup required to serve global audiences with consistent response times.
Web Functions also integrates with Amazon CloudFront to handle applications that combine static and dynamic content. Developers can set a Web Function endpoint as the origin for a CloudFront distribution. Static assets are served from the cache, while dynamic requests route to the Web Function. The launch improves the private-origin experience by allowing CloudFront origin access control to be attached directly to Web Function endpoints, ensuring only the distribution can invoke the function.
AWS Lambda Web Functions is now available in US East (N. Virginia), US East (Ohio), US West (Oregon), Asia Pacific (Tokyo), and Europe (Ireland). At launch, the service runs Node.js 24 on Arm64 processors and supports Amazon Virtual Private Cloud connectivity for accessing resources within a VPC.
Source: AWS
