Moto is a Python library that emulates AWS service APIs in-process for testing and local development. It intercepts boto3/botocore HTTP requests via a custom botocore stubber, dispatches them to per-service in-memory backends registered through a BackendDict pattern, and returns AWS-compatible responses. The library supports decorator/context-manager use, a standalone Flask-based server mode, and an HTTPS proxy mode, making it usable from Python tests, CI pipelines, and non-Python SDKs via a local endpoint.