aws-inmemory-services

In-memory implementations of 159 AWS services written in Rust. All services run as a single binary on separate ports, are compatible with the AWS CLI and SDKs, and require no external dependencies. All state is held in memory — there is no disk persistence. Restarting the server clears all data.

Getting Started

Prerequisites

• Rust (1.70+)
• AWS CLI v2 (for integration tests)

Build

cargo build --release

Run

./target/release/aws-inmemory-services

All 159 services start on their default ports. Override any port with --<service>-port <PORT>, and set region/account with --region and --account-id:

./target/release/aws-inmemory-services --region eu-west-1 --account-id 123456789012

Connecting with the AWS CLI

Point the AWS CLI at any service using --endpoint-url and skip authentication:

aws s3api create-bucket \
  --bucket my-bucket \
  --endpoint-url http://localhost:9000 \
  --no-sign-request

aws dynamodb create-table \
  --table-name MyTable \
  --attribute-definitions AttributeName=pk,AttributeType=S \
  --key-schema AttributeName=pk,KeyType=HASH \
  --billing-mode PAY_PER_REQUEST \
  --endpoint-url http://localhost:8000 \
  --no-sign-request

Connecting with AWS SDKs

import { S3Client, PutObjectCommand } from "@aws-sdk/client-s3";

const client = new S3Client({
  endpoint: "http://localhost:9000",
  region: "us-east-1",
  credentials: { accessKeyId: "test", secretAccessKey: "test" },
  forcePathStyle: true,
});

await client.send(new PutObjectCommand({
  Bucket: "my-bucket",
  Key: "hello.txt",
  Body: "Hello, world!",
}));

Services (159)

All services are organized by category. Click the category link for detailed documentation including supported operations, CLI examples, SDK examples, and wire protocol details.

Compute (13 services) — Full Documentation

Service	Port	Operations
EC2	10001	9
ECS	10003	12
EKS	10004	4
ECR	10002	4
Lambda	9001	22
Batch	10007	8
Lightsail	10005	4
Outposts	10009	4
Auto Scaling	10011	3
Elastic Beanstalk	10008	3
App Runner	10006	4
EC2 Image Builder	10010	4
GameLift	10156	4

Storage (5 services) — Full Documentation

Service	Port	Operations
S3	9000	26
EFS	9600	15
FSx	10147	4
Backup	10146	8
Storage Gateway	10148	4

Databases (9 services) — Full Documentation

Service	Port	Operations
DynamoDB	8000	16
RDS	10012	6
ElastiCache	10014	3
Neptune	10016	3
DocumentDB	10013	3
Timestream	10017	8
Keyspaces	10015	8
MemoryDB	6379	21
Redshift	10060	3

Networking & Content Delivery (10 services) — Full Documentation

Service	Port	Operations
API Gateway	4567	30
CloudFront	10021	4
Route 53	10022	4
ELB	10027	6
VPC Lattice	10023	4
Direct Connect	10025	4
Global Accelerator	10026	4
Cloud Map	10024	4
Network Firewall	10048	8
App Mesh	10158	4

Security, Identity & Compliance (19 services) — Full Documentation

Service	Port	Operations
IAM	10033	9
Cognito	9229	33
KMS	7600	22
Secrets Manager	7700	11
WAF	10035	8
Shield	10036	4
GuardDuty	10037	4
ACM	10034	4
Macie	10039	4
Inspector	10038	4
Security Hub	10046	4
Security Lake	10041	4
Verified Permissions	10042	4
CloudHSM	10044	4
RAM	10045	4
Directory Service	10043	4
IAM Identity Center	10049	4
Firewall Manager	10047	4
Detective	10040	4

Management & Governance (16 services) — Full Documentation

Service	Port	Operations
CloudFormation	10070	3
CloudWatch	10067	3
CloudTrail	10071	4
CloudWatch Logs	9201	17
Organizations	10076	8
Config	9500	19
SSM Parameter Store	9100	10
Trusted Advisor	10078	4
Health	10074	4
Control Tower	10073	4
Compute Optimizer	10072	4
License Manager	10075	4
Proton	10077	4
Managed Grafana	10068	4
Managed Prometheus	10069	4
X-Ray	10089	4

Developer Tools (7 services) — Full Documentation

Service	Port	Operations
CodeBuild	10084	4
CodePipeline	10087	4
CodeCommit	10085	4
CodeDeploy	10086	4
CodeArtifact	10083	8
CodeCatalyst	10082	4
FIS	10088	4

Analytics (18 services) — Full Documentation

Service	Port	Operations
Athena	10050	4
Glue	10065	12
EMR	10053	4
OpenSearch	10058	4
Kinesis	4568	15
Firehose	4573	10
QuickSight	10059	4
CloudSearch	10051	3
MSK	10057	4
Kinesis Video Streams	10055	4
Managed Flink	10056	4
DataZone	10052	4
FinSpace	10054	4
Lake Formation	10066	4
Data Exchange	10062	4
Data Pipeline	10063	4
Entity Resolution	10064	4
Clean Rooms	10061	4

Machine Learning & AI (14 services) — Full Documentation

Service	Port	Operations
SageMaker	10102	4
Bedrock	10093	4
Comprehend	10094	4
Rekognition	10101	4
Textract	10103	4
Transcribe	10104	4
Translate	10105	4
Polly	10100	4
Lex	10098	4
Kendra	10097	4
Personalize	10099	4
Forecast	10095	4
Fraud Detector	10096	4
HealthLake	10107	4

IoT (6 services) — Full Documentation

Service	Port	Operations
IoT Core	10117	4
IoT Events	10118	4
IoT SiteWise	10121	4
IoT TwinMaker	10122	4
IoT Greengrass	10120	4
IoT FleetWise	10119	4

Application Integration (9 services) — Full Documentation

Service	Port	Operations
SNS	9911	17
SQS	9324	23
EventBridge	9195	15
AppSync	9700	19
Step Functions	8083	15
SWF	10115	4
MQ	10113	4
MWAA	10114	4
Service Catalog	9400	16

Business Applications (7 services) — Full Documentation

Service	Port	Operations
Connect	10124	4
Chime	10123	4
WorkDocs	10126	4
WorkMail	10127	4
WorkSpaces	10152	4
Pinpoint	10125	4
SES	9300	5

Media Services (6 services) — Full Documentation

Service	Port	Operations
MediaConvert	10134	4
MediaLive	10135	4
MediaPackage	10136	4
MediaStore	10137	4
IVS	10133	4
Elastic Transcoder	10132	4

Migration & Transfer (6 services) — Full Documentation

Service	Port	Operations
DMS	10018	4
DataSync	10138	4
Transfer Family	10141	4
Migration Hub	10140	4
Mainframe Modernization	10139	4
DRS	10149	4

Cost Management (3 services) — Full Documentation

Service	Port	Operations
Cost Explorer	10131	4
Budgets	10130	4
Billing Conductor	10129	4

Other Services (11 services) — Full Documentation

Service	Port	Operations
Amplify	10154	4
AppFlow	10112	4
AppFabric	10128	4
B2BI	10116	4
Braket	10150	4
Q Business	10108	4
DevOps Guru	10106	4
Device Farm	10155	4
Ground Station	10151	4
Location Service	10153	4
Managed Blockchain	10157	4

Running Tests

Unit Tests

cargo test

Integration Tests

Integration tests use the AWS CLI to exercise all API operations. Each script builds the binary, starts the server on isolated ports, runs all test cases, and reports pass/fail counts.

# Run individual service tests
bash tests/s3_integration.sh
bash tests/dynamodb_integration.sh
bash tests/lambda_integration.sh
bash tests/sns_integration.sh
bash tests/sqs_integration.sh

# Run all integration tests
for f in tests/*_integration.sh; do bash "$f"; done

See the tests/ directory for the full list of 159 integration test scripts.

Differences from AWS

This is a local development tool, not a production replacement. Key differences:

• In-memory only — all state is lost when the server stops. No disk persistence or replication.
• No authentication — all requests are accepted without signature verification. Use --no-sign-request.
• No TLS — the server speaks plain HTTP only.
• Single-process — no distributed behavior.
• S3 versioning — versioning status can be toggled but version history is not maintained. Only the latest version of each object is stored.
• SNS subscriptions auto-confirm — all subscriptions are immediately confirmed without requiring endpoint verification.
• SNS message delivery — messages are accepted and assigned IDs but not actually delivered to endpoints.
• SQS permissions stored but not enforced — AddPermission / RemovePermission update the queue's policy, but no access checks are performed.
• DynamoDB expressions — basic KeyConditionExpression, UpdateExpression (SET, REMOVE), FilterExpression, and ProjectionExpression are supported. Transactions, GSIs/LSIs, and streams are not implemented.
• Lambda invocation — Invoke returns a stub 200 response. Functions are not actually executed.
• Firehose delivery — records are accepted and stored in memory but not delivered to any destination.
• MemoryDB clusters — clusters are created with simulated metadata but no actual Redis instances are started.
• Cognito authentication — auth flows return stub token responses. No actual JWT signing or token validation is performed.
• API Gateway invocations — the service manages REST API configuration but does not route or proxy actual HTTP requests.
• KMS cryptography is simulated — Encrypt/Decrypt, Sign/Verify produce deterministic fake outputs. No actual cryptographic operations are performed.
• Secrets Manager deletion is immediate — DeleteSecret with --force-delete-without-recovery removes the secret immediately.
• EventBridge rules do not evaluate events — PutEvents accepts events but does not match them against rules or invoke targets.
• Step Functions executions do not run — StartExecution creates an execution in RUNNING state but does not evaluate the state machine definition.
• SSM SecureString values are stored in plaintext — no KMS encryption is performed.
• CloudWatch Logs FilterLogEvents uses substring matching — not CloudWatch Logs filter syntax.
• SES emails are not delivered — SendEmail accepts the request but does not deliver email. All identities are auto-verified.
• Service Catalog provisioning is simulated — ProvisionProduct creates a record but does not deploy CloudFormation stacks.
• Config recording is simulated — recorder toggling is tracked but resources are not actually monitored.
• EFS file systems are immediately available — no provisioning delay. Mount targets are simulated.
• AppSync GraphQL APIs are simulated — APIs are created with synthetic URIs but no actual GraphQL endpoint is running.
• No CloudWatch metrics — no metrics integration.
• Encryption attributes are accepted but not applied — KMS-related attributes are stored but data is not encrypted.

CLI Options

Flag	Default	Description
--region	us-east-1	AWS region used in ARNs
--account-id	000000000000	AWS account ID used in ARNs
--<service>-port	(see tables above)	Port for the specified service

Every service has a --<service>-port flag. See the service tables above for default port assignments.

License

This project is for local development and testing purposes.