AWS Lambda MicroVMs: I Tested the New Stateful Serverless Primitive

What just happened On June 22, 2026, AWS quietly launched Lambda MicroVMs. Not a Lambda feature update. A new compute primitive sitting between Lambda Functions (stateless, 15-min max) and EC2 (full VM, you manage everything). Each MicroVM is an isolated Firecracker VM with its own HTTPS endpoint, running your code from a pre-built snapshot. Stateful. Up to 8 hours. Suspend when idle, resume on demand. I tested it the same week. Here's what I found. The test setup A minimal Python HTTP server packaged as a Dockerfile: from http.server import HTTPServer , BaseHTTPRequestHandler import json , time , os class Handler ( BaseHTTPRequestHandler ): start_time = time . time () request_count = 0 def do_GET ( self ): Handler . request_count += 1 body = json . dumps ({ " message " : " Hello from Lambda MicroVM! " , " uptime_seconds " : round ( time . time () - Handler . start_time , 2 ), " requests_served " : Handler . request_count , " pid " : os . getpid () }) self . send_response ( 200 ) self . send_header ( " Content-Type " , " application/json " ) self . end_headers () self . wfile . write ( body . encode ()) HTTPServer (( " 0.0.0.0 " , 8080 ), Handler ). serve_forever () The Dockerfile: FROM public.ecr.aws/lambda/microvms:al2023-minimal RUN dnf install -y python3 && dnf clean all WORKDIR /app COPY app.py . EXPOSE 8080 CMD ["python3", "app.py"] How it works Three steps: Zip code + Dockerfile → upload to S3 create-microvm-image builds the container, starts the app, takes a Firecracker snapshot of memory and disk run-microvm launches from that snapshot Every launch resumes from the pre-initialized state. No cold boot. Your app is already running the moment the MicroVM starts. aws lambda-microvms create-microvm-image \ --name hello-microvm-test \ --code-artifact "uri=s3://my-bucket/artifact.zip" \ --base-image-arn arn:aws:lambda:us-east-1:aws:microvm-image:al2023-1 \ --build-role-arn arn:aws:iam::123456789:role/MicroVMBuildRole Image build took about 3 minutes. Once done: aw