Every developer building on AWS eventually runs into the same frustrations: waiting for deployments just to verify a small change, needing an internet connection for local development, watching cloud costs grow during testing, and discovering issues in CI that could have been caught earlier.
That's exactly why we built LocalEmu.
LocalEmu is an open-source AWS emulator that lets you build and test against AWS APIs entirely on your own machine. It supports 132 AWS services and works with the tools you already use every day—AWS CLI, boto3, Terraform, AWS CDK, and Pulumi. Instead of changing your workflow, you simply point your tools to localhost:4566 and continue developing.
Unlike many local emulators that only mock API responses, LocalEmu focuses on realistic behavior where it matters most. Lambda functions execute using the official AWS runtime images. EC2 instances run as real containers connected through a virtual network with enforced security groups. RDS uses real PostgreSQL and MySQL engines, and optional IAM policy enforcement allows you to validate authorization rules before deploying to AWS.
Getting started takes only a couple of commands:
