AWS, locally.

98 services. One binary. Built-in devtools.

$ npx cloudmock

Three steps. No configuration.

1

Install

One command. No dependencies, no Docker, no cloud account.

npx cloudmock
2

Point your SDK

Override the endpoint in your AWS SDK config.

const client = new S3Client({
  endpoint: "http://localhost:4566",
});
3

Open Devtools

Inspect services, trace requests, and test failure scenarios in the browser.

http://localhost:4500

Everything you need to develop locally

98 AWS Services

25 services with full API emulation -- S3, DynamoDB, SQS, Lambda, and more -- plus 73 CRUD stubs. Test your integrations without an AWS account.

Built-in Devtools

Topology map, request tracing, metrics dashboard, and chaos engineering. All accessible at localhost:4500.

8 Language SDKs

Node, Go, Python, Java, Rust, Swift, Kotlin, and Dart. Use your existing AWS SDK -- just change the endpoint.

IAM Enforcement

Full policy evaluation, credential verification, or no-auth mode. Test your IAM policies locally before deploying.

Chaos Engineering

Inject failures, latency, and errors to test your application's resilience before it hits production.

Zero Config

Works out of the box. No Docker required. No cloud account. No YAML files. Start building in seconds.

98 AWS services

25 services with full API emulation and 73 additional services with CRUD stubs. Every service runs in-process with persistent state.

Account
ACM
ACM PCA
Amplify
API Gateway
AppConfig
Application Auto Scaling
AppSync
Athena
Auto Scaling
Backup
Batch
Bedrock
Cloud Control API
CloudFormation
CloudFront
CloudTrail
CloudWatch
CloudWatch Logs
CodeArtifact
CodeBuild
CodeCommit
CodeConnections
CodeDeploy
CodePipeline
Cognito
Config
Cost Explorer
Data Firehose
DMS
DocumentDB
DynamoDB
EC2
ECR
ECS
EKS
Elastic Beanstalk
Elastic Load Balancing
ElastiCache
Elasticsearch
EMR
EventBridge
EventBridge Pipes
EventBridge Scheduler
FIS
Glacier
Glue
IAM
Identity Store
IoT Core
IoT Data Plane
IoT Wireless
Kafka (MSK)
Kinesis
Kinesis Data Analytics
KMS
Lake Formation
Lambda
Managed Blockchain
MediaConvert
MemoryDB
Amazon MQ
MWAA (Airflow)
Neptune
OpenSearch
Organizations
Pinpoint
RAM
RDS
Redshift
Resource Groups
Resource Groups Tagging API
Route 53
Route 53 Resolver
S3
S3 Tables
SageMaker
Secrets Manager
Serverless Application Repository
Service Discovery
SES
Shield
SNS
SQS
SSM Parameter Store
SSO Admin
Step Functions
STS
Support
SWF
Textract
Timestream Write
Transcribe
Transfer Family
Verified Permissions
WAF Regional
WAFv2

Free for local dev and internal use. Always.

CloudMock is source-available under the Business Source License. Use it locally, host it internally, run it in CI -- no limits. Converts to Apache 2.0 on April 1, 2030.