kumo, a lightweight AWS service emulator written in Go

A lightweight AWS service emulator written in Go.

It lets you quickly set up a compatible environment for local development and CI/CD testing without needing real AWS.

• Runs as a single binary, and also supports Docker-based execution.
• Operates without authentication, reducing the burden of preparing AWS credentials in automation pipelines.
• The default endpoint is localhost:4566.
• Setting KUMO_DATA_DIR lets you persist data as per-service JSON files; if unset, it runs in-memory only.
• All requests are logged in structured format — at INFO level you can see method, path, status code, latency, etc., and at DEBUG level you can even see the request body.
• Additional test endpoints are provided under /kumo/ to query the list of sent emails via SES v2 and the list of sent messages via Pinpoint SMS Voice v2.

The supported scope covers 76 AWS services.

• Storage: S3, DynamoDB, EBS, Glacier, etc.
• Compute: Lambda, EC2, Batch, etc.
• Containers: ECS, ECR, EKS
• Databases: RDS, Neptune, Redshift
• Messaging/Integration: SQS, SNS, EventBridge, Kinesis, etc.
• Security/Identity: IAM, KMS, Secrets Manager, Cognito, etc.
• Monitoring/Logging: CloudWatch, CloudTrail, X-Ray

Examples include creating and uploading to S3 buckets, sending and receiving SQS queue messages, handling DynamoDB tables/items, and creating and retrieving Secrets Manager secrets.

Distributed under the MIT License.