AWS Finally Built Its Own AWS Emulator

AWS has developed its own emulator for AWS APIs, called AWS Emulator. This tool allows developers to test their software without needing an AWS account or making actual calls to AWS services. Instead, the emulator serves as a local program that mimics an AWS API endpoint. To use it, developers simply set environment variables to point their AWS CLI or SDK at the emulator's endpoint, and then run their code as they normally would.

The emulator is particularly useful for building and testing purposes, but it should not be used for production workloads or security testing. To install the emulator, users need to have AWS CLI version 2.35.0 or later. Once installed, they can point their SDK at the running emulator by setting the appropriate environment variables. The emulator's performance closely matches that of AWS services, as evidenced by fidelity scores published with each release.

To ensure compatibility with AWS Emulator, users can check whether their project is expected to work with the emulator. Any gaps or issues can be found in the repository's issues/ and issues/things-that-do-not-work/ directories. For modifications to the emulator or using it in embedded mode, users should refer to the build cost guidance provided. AWS Emulator serves HTTPS on 127.0.0.1:9297 and uses a self-signed certificate.

By default, the emulator collects and reports usage data to AWS for insight into its usage. Telemetry is on by default, but users can disable it by starting the emulator with the --telemetry option set to off, setting the EMULATOR_TELEMETRY variable to off, or adding specific lines to the config.toml file. For embedded mode, telemetry can be turned off by passing appropriate options when creating the emulator.

Building the emulator from source is supported on Linux (x86_64 and aarch64) and requires similar build costs as building from source. For Windows and macOS users, it is recommended to use the Docker path instead. The emulator is licensed under the CC0 1.0 Universal (CC0-1.0) License, except for the code in the vendor/ directory, which is under the Apache License 2.0.