Test your applications against AWS locally with AWS Emulator

Summary

• AWS announces AWS Emulator, a local emulator for Amazon Web Services that runs on a user's machine.
• The AWS CLI, AWS SDKs, and coding agents interact with the emulator over a local HTTPS endpoint using standard AWS APIs.
• There is no additional service fee for the emulator; users pay only for AWS resources when deploying to the cloud.
• The source code is available on GitHub.
• Installation on Linux uses RPM or Debian packages, while macOS and Windows users run the emulator in Docker.
• Starting the emulator generates credentials, a config file, and a certificate stored in ~/.aws/emulator/9297/.
• Users set environment variables to direct AWS SDKs to the local endpoint without changing application code.
• The emulator is implemented in Rust to minimize CPU & memory usage on laptops.
• It supports APIs defined in the AWS API models repository on GitHub to ensure request & error shapes match AWS.
• The emulator serves HTTPS on 127.0.0.1:9297 by default, accessible only from the local computer.
• Access key IDs generated by the emulator start with "EMULATOR" to distinguish them from real AWS keys.
• The emulator uses a single account ID (000000000000) and rejects requests signed with keys other than its own.
• An embedded mode allows instantiation directly inside test processes for the AWS SDK for Rust, enabling parallel execution with isolated state.
• Fidelity tests verify that emulator responses match real AWS behavior on status codes, bodies, error codes, messages, & created resources.
• Release notes publish fidelity scores as k of n for each service, with the test suite available in the aws-emulator-evaluation-suite repository.
• Unimplemented operations return HTTP 501 (Not Implemented).
• The emulator is built & maintained by agents using Amazon Bedrock AgentCore Runtime Instances, AWS CodePipeline, & AWS CodeCommit.
• Independent security agents review code changes adversarially before release.
• The emulator listens only on the local computer & does not evaluate IAM policies or resource-based policies like AWS does.
• AWS Emulator is generally available with no additional service fee.
• At launch, the emulator does not support cross-account or cross-Region behavior.
• Users can check fidelity scores in the AWS Emulator documentation & regional availability on the AWS Capabilities by Region page.