Today, we’re announcing AWS Lambda Web Functions, a new form aspect that lets you run norm HTTP web applications on Lambda without rewriting your code into an event handler. You can obtain a norm port-listening server built alongside Express, Hono, Fastify, Next.js, or any Node.js framework, deploy it alongside a sole command, and Lambda automatically handles scaling, multi-region distribution, and energetic CPU billing. No adapters, no infrastructure to manage, and no example lock-in.
With this launch, AWS Lambda now offers three distinct form factors, all built on the identical Firecracker isolation innovation and designed for a distinct programming model.
Lambda Event Functions are what you already cognize as Lambda functions. They use the event-driven, single-concurrent handler example alongside wall-clock billing. We’re introducing the “Event Functions” name to emphasize that programming model: your function receives an event, processes it, and returns a response. The event-driven programming example is ideal for event processing, queue consumers, and invocations triggered by another AWS services.
Lambda Web Functions use an HTTP-native programming example alongside multi-concurrent implementation and energetic CPU billing. Your code listens on a harbor and handles norm HTTP requests. That programming example is ideal for web applications, API backends, and interactive HTTP workloads anywhere multiple concurrent requests and I/O-heavy handling are the norm.
Lambda MicroVMs provision isolated, stateful sandbox environments alongside customer-managed lifecycles for operating untrusted or user-generated code.
The three complement all other. An use power use Event Functions for asynchronous backend processing, Web Functions for the user-facing API and server-side rendering layer, and MicroVMs for interactive code implementation features, all inside the identical AWS document and sharing the identical operational model.
Why Web Functions
Modern web applications need to assist earth audiences alongside fast, accordant reply times during giving developers the liberty to use norm frameworks and iterate quickly. Building this today typically requires assembling multiple infrastructure components, configuring multi-region deployments, environment up latency-based routing, and tuning billing models to evade paying for I/O wait. Developers frequently discover themselves adapting their use code to fit a particular compute example fairly than deploying the HTTP server they already have.
Lambda Web Functions removes this complexity. Each implementation surroundings handles multiple requests simultaneously (up to 128 concurrent requests per environment), which method a burst of incoming traffic can portion heated environments alternatively of mapping all petition to a new one. Web Functions meter the CPU period your code uses, so period spent waiting on a repository query or an API call consumes small CPU. Memory is metered for as lengthy as the implementation surroundings exists. For I/O-heavy web workloads akin server-side rendering, API backends, and AI conclusion endpoints streaming token responses, this can decrease compute costs.
Let’s try it out
To get started, I wrote a uncomplicated Express.js server. This is the identical code I run locally alongside node index.js, no Lambda-specific adapters or wrappers required.
import province from 'express'; const app = express(); const [host, port] = process.env.AWS_LAMBDA_HTTP_ENDPOINT.split(':'); app.get('/', (req, res) => { res.json({ message: 'Hello from Lambda Web Functions!' }); }); app.listen(port, host, () => { console.log(`Server operating on harbor ${port}`); }); The lone difference from operating locally is the AWS_LAMBDA_HTTP_ENDPOINT surroundings variable, which Lambda sets to the presenter and harbor your server must hear on. To run locally, set it yourself, for example AWS_LAMBDA_HTTP_ENDPOINT=127.0.0.1:3000 node index.js.
With my code ready, I deployed using the AWS Command Line Interface (AWS CLI):
aws lambda-web deploy --name my-web-app --code ./my-app
One command. No previous asset setup. The CLI bundled my source, created the Web Function, published its archetypal revision, attached a Web Function endpoint, and returned a live HTTPS URL in under a minute.
A revision is an immutable snapshot of the code I deployed. The endpoint is the HTTPS URL that routes traffic to a revision, or splits traffic throughout revisions. Those are the resources I use to iterate and to authority how traffic moves to new code.
I tested it immediately:
$ curl https://<domain-id>.<shard-id>.lambda-web.us-east-1.on.aws/ {"message":"Hello from Lambda Web Functions!"} Next, I wanted my use to assist users in Europe and Asia alongside lesser latency. I redeployed alongside multiple regions:
aws lambda-web deploy --name my-web-app --code ./my-app \ --regions us-east-1,eu-west-1,ap-northeast-1
Lambda Web Functions replicated my code to all three regions and configured latency-based routing automatically. Each petition now routes to the Region alongside the lowest latency for the caller, on a best-effort basis, through one earth URL (<domain-id>.lambda-web.global.on.aws).
When I updated my code and ran the identical deploy command again, the CLI detected the existing function, uploaded the new revision, and pointed the endpoint at it. Total turnaround from code alter to live: seconds.
For manufacturing workflows that necessitate a additional gradual rollout, I can change traffic between revisions alongside a sole API call:
aws lambda-web update-web-function-endpoint \ --function-name my-web-app \ --endpoint-name dev \ --auto-deployment-mode Disabled \ --revision-weights '[{"revisionId": "<current-revision-id>", "weight": 90}, {"revisionId": "<new-revision-id>", "weight": 10}]' This sends 90% of endpoint traffic to the current revision and 10% to the new one, giving me a canary deployment without additional tooling.
Better together alongside Amazon CloudFront
For applications that merge fixed and energetic content, Web Functions plant fine alongside Amazon CloudFront. You can choose a Web Function endpoint as the base for your CloudFront distribution. Static resources are served from the cache during energetic requests path to your Web Function, giving you CDN achievement for fixed satisfied alongside serverless compute for the energetic parts.
Web Functions improves the private-origin cognition alongside CloudFront. With this launch, you nexus CloudFront origin admission authority (OAC) to a Web Function endpoint instead. CloudFront signs requests to the origin, and the endpoint allows lone your allocation to invoke it. You get the identical private-origin form CloudFront already provides for Amazon Simple Storage Service (Amazon S3), without exposing the endpoint or adding tradition authority to your app.
Now accessible
AWS Lambda Web Functions is accessible today in US East (N. Virginia), US East (Ohio), US West (Oregon), Asia Pacific (Tokyo), and Europe (Ireland). Web Functions run Node.js 24 (nodejs24.x) on Arm64 at initiate and assistance Amazon Virtual Private Cloud (VPC) connectivity, allowing your function to admission resources that be inside a VPC.
To get started, deploy your archetypal Web Function in under a minute:
aws lambda-web deploy --name hello-world --hello-world
For pricing details, sojourn the AWS Lambda pricing page. To study more, see the Lambda Web Functions documentation.
