AWS made AWS Emulator generally available on 11 November 2026. Developers can direct AWS API calls to a local endpoint instead of deploying test resources to an AWS account. The tool is intended for local development and continuous integration, where a shorter test loop can help teams find errors before a cloud deployment.
How the local loop works
After starting the emulator, developers point the AWS CLI or an AWS SDK to its local HTTPS endpoint and use credentials generated by the tool. Supported API operations can create and inspect emulated resources. Each instance keeps its resources in memory until it stops. An operation the emulator does not implement returns HTTP 501.
AWS provides Linux packages. On macOS and Windows, users build and run a Docker image using the documented setup. Tests written with the AWS SDK for Rust can also run the emulator inside the test process. These options support local testing; they do not reproduce an entire production AWS environment.
What a passing local test cannot prove
The emulator matches AWS most closely for control-plane operations, such as creating and listing resources. Fidelity varies by service and feature, especially for data-plane operations and infrastructure-as-code tools. AWS publishes fidelity tests and per-service scores with releases. Teams can inspect those results for the operations their own tests use.
The AWS user guide names further limits. The emulator does not evaluate AWS Identity and Access Management (IAM) or resource-based policies the way AWS does, so a request that passes locally might be denied in AWS. One instance does not keep resources separate by account or Region. AWS also says it has not tested the tool for long-running use or load testing, and its in-memory resources disappear when it stops.
The practical use is fast local and CI feedback, followed by checks in AWS for permissions, regional behavior, and the complete application before production. A local pass is useful evidence for the operations tested, not proof that the deployment will behave identically in the cloud.
