AWS Lambda Web Functions

AWS announced Lambda Web Functions, a new Lambda form factor that runs standard HTTP servers on Lambda without rewriting apps as event handlers. It accepts any Node.js framework (Express, Hono, Fastify, Next.js, etc.), automatically handles scaling and multi-region distribution, and uses active CPU billing. Lambda now exposes three distinct form factors - Event Functions (event-driven, single-concurrency, wall-clock billing), Web Functions (HTTP-native, multi-concurrent execution), and MicroVMs (isolated, stateful sandboxes) - so teams can mix models for backend processing, user-facing APIs/SSR, and sandboxed code execution. Web Functions let an execution environment serve up to 128 concurrent requests, meter CPU time (so I/O wait costs less), and bill memory while the environment exists, which lowers compute costs for I/O-heavy workloads like server-side rendering and streaming AI inference.

Deployment is single-command via the aws lambda-web CLI, which bundles code, publishes immutable revisions, attaches HTTPS endpoints, and can replicate to multiple regions with automatic latency-based routing via a global URL. The runtime sets AWS_LAMBDA_HTTP_ENDPOINT for apps to bind a host:port. Endpoints can split traffic across revisions for canary rollouts using revision weights, and integrate with CloudFront as a private origin using Origin Access Control so static assets cache at the CDN while dynamic requests hit the Web Function. Lambda Web Functions is available today.