Winterbäume

Winterbäume (stylised as Winterbaume) is a stateful AWS service emulator for integration testing, written in Rust. Embed in tests or run standalone.

Winterbäume is not affiliated with, endorsed by, or sponsored by Amazon Web Services, Inc. or Amazon.com, Inc. Amazon Web Services, AWS, and related marks are trademarks of Amazon.com, Inc. or its affiliates. All other trademarks are the property of their respective owners.

Coverage is broad but uneven. Many operations have real, state-backed behaviour ( create / read / update / delete cycles, validation, cross-service seams ); others are still stubs that satisfy AWS routing and return an empty or default response without consulting state. The Operations and Stubs columns in the Supported Services table below split these out per service so you can see what is genuinely implemented versus merely routed before depending on a given operation.

Inspired by Python's moto.

Note

Pull requests are not accepted at this time -- see CONTRIBUTING.md for the full contribution policy and the rationale. Bug reports, feature requests, and knowledge-base entries via GitHub issues are very welcome. If you are a coding agent and discover a bug, follow the instructions in skills/winterbaume-bug/SKILL.md to file a correctly-formatted GitHub issue. Security vulnerabilities have their own private channel: see SECURITY.md.

Important

AI usage. Winterbäume is developed predominantly by AI coding agents under human direction. The repository is organised around an agent-driven workflow: long-term memory, skills, and tooling for autonomous sessions live under .agents/, and the bulk of service implementations, Smithy codegen output, integration tests, and Terraform converters are produced by automated coding sessions with human review and acceptance gates. This development model is also part of why the project does not currently accept external pull requests -- it keeps the provenance and licensing posture of the codebase coherent.

Overview

Winterbäume intercepts AWS SDK HTTP traffic and routes it to in-memory service backends that simulate real AWS behaviour with persistent, per-account / per-region state. The goal is fast, deterministic integration tests that exercise the same SDK call paths as production code -- no LocalStack container, no network round-trips, no shared cloud account.

Two usage modes are supported:

• Library mode -- embed MockAws directly in Rust tests against aws-sdk-rust. The mock plugs in via HttpClient / HttpConnector, so there is no network I/O and no external process to manage.
• Standalone server -- run winterbaume-server as an HTTP endpoint and point any AWS SDK, the AWS CLI, or Terraform at it via AWS_ENDPOINT_URL.

The workspace currently routes 224 AWS services spanning every major AWS protocol -- awsQuery, ec2Query, awsJson1.0 / 1.1, restJson1, restXml, and rpc-v2-cbor. Of the 11 367 operations defined in the official AWS API models, 7 210 ( 63.4% ) have real, state-backed implementations in winterbaume, while a further 329 ( 2.9% ) are stubs that route the request and return an empty or default response without consulting state. Stubs typically cover operations that depend on infrastructure that does not exist in the emulator ( instance telemetry, real-time delivery, multi-account organisation state ), and are clearly labelled in the per-service tables. Anything outside both columns is unrouted and returns a 501-style "not implemented" response. A companion Terraform state converter layer ( winterbaume-terraform ) can inject Terraform state into the emulator and extract it back, enabling seeding mock environments from existing .tfstate files and round-trip validation against the official AWS provider schema.

Service backends are hand-written for behaviour and validation, while wire-level types and serialisers are generated from Smithy models via the in-tree smithy-codegen tool. Correctness is validated in layers: integration tests against real aws-sdk-rust clients, ports of moto's behavioural test suite where applicable, and end-to-end Terraform suites that drive terraform apply against an in-process server. Operation-count coverage is a prioritisation signal rather than a behavioural guarantee, so before relying on a particular operation, check the per-crate README for whether it is implemented, stubbed, or unrouted.

Supported Services

The Operations column shows real, state-backed implementations. The Stubs column shows operations whose handler routes the request and returns an empty/default response without real behaviour ( either annotated with // STUB[<category>]: ... in handlers.rs, or detected heuristically as a body that produces a default response without consulting state ). The two columns are disjoint -- stubs are excluded from the operation count.

Service	Crate	Protocol	Operations	Stubs	moto	floci	kumo
Account	winterbaume-account	restJson1	14/15 (93.3%)	1/15 (6.7%)	3/15 (20.0%)	0/15 (0.0%)	0/15 (0.0%)
ACM	winterbaume-acm	awsJson1.1	16/17 (94.1%)	0/17 (0.0%)	11/17 (64.7%)	0/17 (0.0%)	6/17 (35.3%)
ACM PCA	winterbaume-acmpca	awsJson1.1	23/23 (100.0%)	0/23 (0.0%)	17/23 (73.9%)	0/23 (0.0%)	0/23 (0.0%)
AIOps	winterbaume-aiops	restJson1	11/11 (100.0%)	0/11 (0.0%)	0/11 (0.0%)	0/11 (0.0%)	0/11 (0.0%)
AMP/Prometheus	winterbaume-amp	restJson1	17/44 (38.6%)	0/44 (0.0%)	17/44 (38.6%)	0/44 (0.0%)	0/44 (0.0%)
Amplify	winterbaume-amplify	restJson1	23/37 (62.2%)	0/37 (0.0%)	0/37 (0.0%)	0/37 (0.0%)	9/37 (24.3%)
Amplify Backend	winterbaume-amplifybackend	restJson1	4/31 (12.9%)	0/31 (0.0%)	0/31 (0.0%)	0/31 (0.0%)	0/31 (0.0%)
Amplify UI Builder	winterbaume-amplifyuibuilder	restJson1	28/28 (100.0%)	0/28 (0.0%)	0/28 (0.0%)	0/28 (0.0%)	0/28 (0.0%)
API Gateway	winterbaume-apigateway	restJson1	117/124 (94.4%)	2/124 (1.6%)	78/124 (62.9%)	70/124 (56.5%)	17/124 (13.7%)
API Gateway Management API	winterbaume-apigatewaymanagement	restJson1	3/3 (100.0%)	0/3 (0.0%)	3/3 (100.0%)	0/3 (0.0%)	0/3 (0.0%)
API Gateway V2	winterbaume-apigatewayv2	restJson1	62/103 (60.2%)	0/103 (0.0%)	54/103 (52.4%)	0/103 (0.0%)	0/103 (0.0%)
App Mesh	winterbaume-appmesh	restJson1	38/38 (100.0%)	0/38 (0.0%)	0/38 (0.0%)	0/38 (0.0%)	25/38 (65.8%)
App Runner	winterbaume-apprunner	awsJson1.0	23/37 (62.2%)	0/37 (0.0%)	0/37 (0.0%)	0/37 (0.0%)	0/37 (0.0%)
AppConfig	winterbaume-appconfig	restJson1	45/45 (100.0%)	0/45 (0.0%)	15/45 (33.3%)	0/45 (0.0%)	0/45 (0.0%)
AppConfig Data	winterbaume-appconfigdata	restJson1	2/2 (100.0%)	0/2 (0.0%)	0/2 (0.0%)	0/2 (0.0%)	0/2 (0.0%)
AppFabric	winterbaume-appfabric	restJson1	6/26 (23.1%)	0/26 (0.0%)	0/26 (0.0%)	0/26 (0.0%)	0/26 (0.0%)
AppFlow	winterbaume-appflow	restJson1	9/25 (36.0%)	0/25 (0.0%)	0/25 (0.0%)	0/25 (0.0%)	0/25 (0.0%)
AppIntegrations	winterbaume-appintegrations	restJson1	23/23 (100.0%)	0/23 (0.0%)	0/23 (0.0%)	0/23 (0.0%)	0/23 (0.0%)
Application Auto Scaling	winterbaume-applicationautoscaling	awsJson1.1	13/14 (92.9%)	1/14 (7.1%)	9/14 (64.3%)	0/14 (0.0%)	0/14 (0.0%)
Application Cost Profiler	winterbaume-applicationcostprofiler	restJson1	6/6 (100.0%)	0/6 (0.0%)	0/6 (0.0%)	0/6 (0.0%)	0/6 (0.0%)
Application Discovery Service	winterbaume-applicationdiscoveryservice	awsJson1.1	28/28 (100.0%)	0/28 (0.0%)	0/28 (0.0%)	0/28 (0.0%)	0/28 (0.0%)
Application Insights	winterbaume-applicationinsights	awsJson1.1	33/33 (100.0%)	0/33 (0.0%)	0/33 (0.0%)	0/33 (0.0%)	0/33 (0.0%)
Application Signals	winterbaume-applicationsignals	restJson1	10/23 (43.5%)	3/23 (13.0%)	0/23 (0.0%)	0/23 (0.0%)	0/23 (0.0%)
AppSync	winterbaume-appsync	restJson1	27/74 (36.5%)	0/74 (0.0%)	27/74 (36.5%)	0/74 (0.0%)	3/74 (4.1%)
ARC Zonal Shift	winterbaume-arczonalshift	restJson1	14/15 (93.3%)	1/15 (6.7%)	0/15 (0.0%)	0/15 (0.0%)	0/15 (0.0%)
Artifact	winterbaume-artifact	restJson1	8/8 (100.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)
Athena	winterbaume-athena	awsJson1.1	25/70 (35.7%)	0/70 (0.0%)	27/70 (38.6%)	0/70 (0.0%)	7/70 (10.0%)
Audit Manager	winterbaume-auditmanager	restJson1	15/62 (24.2%)	0/62 (0.0%)	0/62 (0.0%)	0/62 (0.0%)	0/62 (0.0%)
Aurora DSQL	winterbaume-dsql	restJson1	12/12 (100.0%)	0/12 (0.0%)	5/12 (41.7%)	0/12 (0.0%)	0/12 (0.0%)
Auto Scaling	winterbaume-autoscaling	awsQuery	52/66 (78.8%)	0/66 (0.0%)	39/66 (59.1%)	0/66 (0.0%)	0/66 (0.0%)
Auto Scaling Plans	winterbaume-autoscalingplans	awsJson1.1	6/6 (100.0%)	0/6 (0.0%)	0/6 (0.0%)	0/6 (0.0%)	0/6 (0.0%)
Backup	winterbaume-backup	restJson1	105/108 (97.2%)	3/108 (2.8%)	17/108 (15.7%)	0/108 (0.0%)	12/108 (11.1%)
Backup Gateway	winterbaume-backupgateway	awsJson1.0	25/25 (100.0%)	0/25 (0.0%)	0/25 (0.0%)	0/25 (0.0%)	0/25 (0.0%)
Backup Search	winterbaume-backupsearch	restJson1	9/12 (75.0%)	0/12 (0.0%)	0/12 (0.0%)	0/12 (0.0%)	0/12 (0.0%)
Batch	winterbaume-batch	restJson1	39/45 (86.7%)	0/45 (0.0%)	24/45 (53.3%)	0/45 (0.0%)	10/45 (22.2%)
BCM Dashboards	winterbaume-bcmdashboards	awsJson1.0	9/15 (60.0%)	0/15 (0.0%)	0/15 (0.0%)	0/15 (0.0%)	0/15 (0.0%)
BCM Data Exports	winterbaume-bcmdataexports	awsJson1.1	12/12 (100.0%)	0/12 (0.0%)	0/12 (0.0%)	0/12 (0.0%)	0/12 (0.0%)
BCM Recommended Actions	winterbaume-bcmrecommendedactions	awsJson1.0	1/1 (100.0%)	0/1 (0.0%)	0/1 (0.0%)	0/1 (0.0%)	0/1 (0.0%)
Bedrock	winterbaume-bedrock	restJson1	48/101 (47.5%)	0/101 (0.0%)	13/101 (12.9%)	0/101 (0.0%)	0/101 (0.0%)
Bedrock Agent	winterbaume-bedrockagent	restJson1	72/72 (100.0%)	0/72 (0.0%)	11/72 (15.3%)	0/72 (0.0%)	0/72 (0.0%)
Billing	winterbaume-billing	awsJson1.0	12/12 (100.0%)	0/12 (0.0%)	0/12 (0.0%)	0/12 (0.0%)	0/12 (0.0%)
Braket	winterbaume-braket	restJson1	12/17 (70.6%)	0/17 (0.0%)	0/17 (0.0%)	0/17 (0.0%)	0/17 (0.0%)
Budgets	winterbaume-budgets	awsJson1.1	7/26 (26.9%)	0/26 (0.0%)	7/26 (26.9%)	0/26 (0.0%)	0/26 (0.0%)
Chatbot	winterbaume-chatbot	restJson1	15/34 (44.1%)	0/34 (0.0%)	0/34 (0.0%)	0/34 (0.0%)	0/34 (0.0%)
Chime SDK Meetings	winterbaume-chimesdkmeetings	restJson1	12/16 (75.0%)	0/16 (0.0%)	0/16 (0.0%)	0/16 (0.0%)	0/16 (0.0%)
Cloud Control API	winterbaume-cloudcontrol	awsJson1.0	8/8 (100.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)
Cloud Directory	winterbaume-clouddirectory	restJson1	13/66 (19.7%)	0/66 (0.0%)	13/66 (19.7%)	0/66 (0.0%)	0/66 (0.0%)
Cloud9	winterbaume-cloud9	awsJson1.1	13/13 (100.0%)	0/13 (0.0%)	0/13 (0.0%)	0/13 (0.0%)	0/13 (0.0%)
CloudFormation	winterbaume-cloudformation	awsQuery	40/90 (44.4%)	3/90 (3.3%)	33/90 (36.7%)	0/90 (0.0%)	8/90 (8.9%)
CloudFront	winterbaume-cloudfront	restXml	156/167 (93.4%)	11/167 (6.6%)	25/167 (15.0%)	0/167 (0.0%)	8/167 (4.8%)
CloudFront KeyValueStore	winterbaume-cloudfrontkeyvaluestore	restJson1	5/6 (83.3%)	0/6 (0.0%)	0/6 (0.0%)	0/6 (0.0%)	0/6 (0.0%)
CloudHSM v2	winterbaume-cloudhsmv2	awsJson1.1	18/18 (100.0%)	0/18 (0.0%)	0/18 (0.0%)	0/18 (0.0%)	0/18 (0.0%)
CloudSearch Domain	winterbaume-cloudsearchdomain	restJson1	2/3 (66.7%)	0/3 (0.0%)	0/3 (0.0%)	0/3 (0.0%)	0/3 (0.0%)
CloudTrail	winterbaume-cloudtrail	awsJson1.1	21/60 (35.0%)	2/60 (3.3%)	16/60 (26.7%)	0/60 (0.0%)	8/60 (13.3%)
CloudTrail Data	winterbaume-cloudtraildata	restJson1	1/1 (100.0%)	0/1 (0.0%)	0/1 (0.0%)	0/1 (0.0%)	0/1 (0.0%)
CloudWatch	winterbaume-cloudwatch	awsJson1.0	38/46 (82.6%)	5/46 (10.9%)	20/46 (43.5%)	0/46 (0.0%)	10/46 (21.7%)
CloudWatch Logs	winterbaume-cloudwatchlogs	awsJson1.1	93/113 (82.3%)	15/113 (13.3%)	51/113 (45.1%)	0/113 (0.0%)	11/113 (9.7%)
CodeArtifact	winterbaume-codeartifact	restJson1	9/48 (18.8%)	0/48 (0.0%)	0/48 (0.0%)	0/48 (0.0%)	0/48 (0.0%)
CodeBuild	winterbaume-codebuild	awsJson1.1	29/59 (49.2%)	0/59 (0.0%)	9/59 (15.3%)	0/59 (0.0%)	0/59 (0.0%)
CodeCommit	winterbaume-codecommit	awsJson1.1	25/79 (31.6%)	0/79 (0.0%)	3/79 (3.8%)	0/79 (0.0%)	0/79 (0.0%)
CodeDeploy	winterbaume-codedeploy	awsJson1.1	15/47 (31.9%)	0/47 (0.0%)	14/47 (29.8%)	0/47 (0.0%)	0/47 (0.0%)
CodeGuru Reviewer	winterbaume-codegurureviewer	restJson1	9/14 (64.3%)	0/14 (0.0%)	0/14 (0.0%)	0/14 (0.0%)	11/14 (78.6%)
CodeGuru Security	winterbaume-codegurusecurity	restJson1	11/13 (84.6%)	0/13 (0.0%)	0/13 (0.0%)	0/13 (0.0%)	0/13 (0.0%)
CodePipeline	winterbaume-codepipeline	awsJson1.1	44/44 (100.0%)	0/44 (0.0%)	8/44 (18.2%)	0/44 (0.0%)	0/44 (0.0%)
CodeStar Notifications	winterbaume-codestarnotifications	restJson1	7/13 (53.8%)	0/13 (0.0%)	0/13 (0.0%)	0/13 (0.0%)	0/13 (0.0%)
Cognito Identity	winterbaume-cognitoidentity	awsJson1.1	20/23 (87.0%)	3/23 (13.0%)	10/23 (43.5%)	0/23 (0.0%)	0/23 (0.0%)
Cognito Identity Provider	winterbaume-cognitoidentityprovider	awsJson1.1	104/122 (85.2%)	18/122 (14.8%)	62/122 (50.8%)	39/122 (32.0%)	17/122 (13.9%)
Cognito Sync	winterbaume-cognitosync	restJson1	11/17 (64.7%)	0/17 (0.0%)	0/17 (0.0%)	0/17 (0.0%)	0/17 (0.0%)
Comprehend	winterbaume-comprehend	awsJson1.1	60/85 (70.6%)	5/85 (5.9%)	63/85 (74.1%)	0/85 (0.0%)	12/85 (14.1%)
Config	winterbaume-config	awsJson1.1	46/97 (47.4%)	3/97 (3.1%)	38/97 (39.2%)	0/97 (0.0%)	9/97 (9.3%)
Connect	winterbaume-connect	restJson1	10/370 (2.7%)	0/370 (0.0%)	10/370 (2.7%)	0/370 (0.0%)	0/370 (0.0%)
Connect Campaigns	winterbaume-connectcampaigns	restJson1	14/22 (63.6%)	0/22 (0.0%)	14/22 (63.6%)	0/22 (0.0%)	0/22 (0.0%)
Connect Contact Lens	winterbaume-connectcontactlens	restJson1	0/1 (0.0%)	0/1 (0.0%)	0/1 (0.0%)	0/1 (0.0%)	0/1 (0.0%)
Connect Participant	winterbaume-connectparticipant	restJson1	7/11 (63.6%)	0/11 (0.0%)	0/11 (0.0%)	0/11 (0.0%)	0/11 (0.0%)
Control Catalog	winterbaume-controlcatalog	restJson1	6/6 (100.0%)	0/6 (0.0%)	0/6 (0.0%)	0/6 (0.0%)	0/6 (0.0%)
Cost and Usage Report Service	winterbaume-costandusagereport	awsJson1.1	7/7 (100.0%)	0/7 (0.0%)	0/7 (0.0%)	0/7 (0.0%)	0/7 (0.0%)
Cost Explorer	winterbaume-costexplorer	awsJson1.1	22/47 (46.8%)	25/47 (53.2%)	0/47 (0.0%)	0/47 (0.0%)	8/47 (17.0%)
Cost Optimization Hub	winterbaume-costoptimizationhub	awsJson1.0	8/8 (100.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)
Data Pipeline	winterbaume-datapipeline	awsJson1.1	19/19 (100.0%)	0/19 (0.0%)	0/19 (0.0%)	0/19 (0.0%)	0/19 (0.0%)
Database Migration Service (DMS)	winterbaume-databasemigration	awsJson1.1	42/119 (35.3%)	0/119 (0.0%)	17/119 (14.3%)	0/119 (0.0%)	0/119 (0.0%)
DataBrew	winterbaume-databrew	restJson1	32/44 (72.7%)	1/44 (2.3%)	24/44 (54.5%)	0/44 (0.0%)	0/44 (0.0%)
DataSync	winterbaume-datasync	awsJson1.1	8/53 (15.1%)	0/53 (0.0%)	6/53 (11.3%)	0/53 (0.0%)	0/53 (0.0%)
DAX	winterbaume-dax	awsJson1.1	6/21 (28.6%)	0/21 (0.0%)	8/21 (38.1%)	0/21 (0.0%)	0/21 (0.0%)
Direct Connect	winterbaume-directconnect	awsJson1.1	7/63 (11.1%)	0/63 (0.0%)	0/63 (0.0%)	0/63 (0.0%)	0/63 (0.0%)
Directory Service	winterbaume-directory	awsJson1.1	4/80 (5.0%)	0/80 (0.0%)	0/80 (0.0%)	0/80 (0.0%)	6/80 (7.5%)
DLM	winterbaume-dlm	restJson1	2/8 (25.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)	5/8 (62.5%)
DynamoDB	winterbaume-dynamodb	awsJson1.0	57/57 (100.0%)	0/57 (0.0%)	39/57 (68.4%)	0/57 (0.0%)	20/57 (35.1%)
DynamoDB Streams	winterbaume-dynamodbstreams	awsJson1.0	4/4 (100.0%)	0/4 (0.0%)	0/4 (0.0%)	0/4 (0.0%)	0/4 (0.0%)
EBS	winterbaume-ebs	restJson1	6/6 (100.0%)	0/6 (0.0%)	6/6 (100.0%)	0/6 (0.0%)	0/6 (0.0%)
EC2	winterbaume-ec2	ec2Query	713/763 (93.4%)	43/763 (5.6%)	223/763 (29.2%)	0/763 (0.0%)	39/763 (5.1%)
EC2 Instance Connect	winterbaume-ec2instanceconnect	awsJson1.1	2/2 (100.0%)	0/2 (0.0%)	1/2 (50.0%)	0/2 (0.0%)	0/2 (0.0%)
ECR	winterbaume-ecr	awsJson1.1	58/58 (100.0%)	0/58 (0.0%)	29/58 (50.0%)	0/58 (0.0%)	11/58 (19.0%)
ECS	winterbaume-ecs	awsJson1.1	63/76 (82.9%)	1/76 (1.3%)	45/76 (59.2%)	0/76 (0.0%)	12/76 (15.8%)
EFS	winterbaume-efs	restJson1	31/31 (100.0%)	0/31 (0.0%)	19/31 (61.3%)	0/31 (0.0%)	0/31 (0.0%)
EKS	winterbaume-eks	restJson1	55/64 (85.9%)	4/64 (6.2%)	17/64 (26.6%)	0/64 (0.0%)	8/64 (12.5%)
Elastic Beanstalk	winterbaume-elasticbeanstalk	awsQuery	7/47 (14.9%)	0/47 (0.0%)	0/47 (0.0%)	0/47 (0.0%)	7/47 (14.9%)
ElastiCache	winterbaume-elasticache	awsQuery	24/75 (32.0%)	0/75 (0.0%)	17/75 (22.7%)	0/75 (0.0%)	7/75 (9.3%)
ELB	winterbaume-elasticloadbalancing	awsQuery	29/29 (100.0%)	0/29 (0.0%)	21/29 (72.4%)	0/29 (0.0%)	0/29 (0.0%)
ELBv2	winterbaume-elasticloadbalancingv2	awsQuery	50/51 (98.0%)	1/51 (2.0%)	33/51 (64.7%)	0/51 (0.0%)	22/51 (43.1%)
EMR	winterbaume-emr	awsJson1.1	54/60 (90.0%)	2/60 (3.3%)	26/60 (43.3%)	0/60 (0.0%)	0/60 (0.0%)
EMR Containers	winterbaume-emrcontainers	restJson1	23/23 (100.0%)	0/23 (0.0%)	8/23 (34.8%)	0/23 (0.0%)	0/23 (0.0%)
EMR Serverless	winterbaume-emrserverless	restJson1	16/22 (72.7%)	0/22 (0.0%)	11/22 (50.0%)	0/22 (0.0%)	11/22 (50.0%)
EventBridge	winterbaume-eventbridge	awsJson1.1	57/57 (100.0%)	0/57 (0.0%)	45/57 (78.9%)	0/57 (0.0%)	15/57 (26.3%)
EventBridge Pipes	winterbaume-pipes	restJson1	10/10 (100.0%)	0/10 (0.0%)	9/10 (90.0%)	0/10 (0.0%)	10/10 (100.0%)
Firehose	winterbaume-firehose	awsJson1.1	12/12 (100.0%)	0/12 (0.0%)	12/12 (100.0%)	0/12 (0.0%)	7/12 (58.3%)
FIS	winterbaume-fis	restJson1	8/26 (30.8%)	0/26 (0.0%)	5/26 (19.2%)	0/26 (0.0%)	0/26 (0.0%)
Forecast	winterbaume-forecast	awsJson1.1	5/63 (7.9%)	0/63 (0.0%)	5/63 (7.9%)	0/63 (0.0%)	17/63 (27.0%)
Free Tier	winterbaume-freetier	awsJson1.0	5/5 (100.0%)	0/5 (0.0%)	0/5 (0.0%)	0/5 (0.0%)	0/5 (0.0%)
FSx	winterbaume-fsx	awsJson1.1	9/48 (18.8%)	0/48 (0.0%)	9/48 (18.8%)	0/48 (0.0%)	0/48 (0.0%)
Glacier	winterbaume-glacier	restJson1	33/33 (100.0%)	0/33 (0.0%)	10/33 (30.3%)	0/33 (0.0%)	4/33 (12.1%)
Glue	winterbaume-glue	awsJson1.1	132/265 (49.8%)	0/265 (0.0%)	96/265 (36.2%)	0/265 (0.0%)	14/265 (5.3%)
Greengrass	winterbaume-greengrass	restJson1	71/92 (77.2%)	0/92 (0.0%)	55/92 (59.8%)	0/92 (0.0%)	0/92 (0.0%)
GuardDuty	winterbaume-guardduty	restJson1	85/87 (97.7%)	2/87 (2.3%)	12/87 (13.8%)	0/87 (0.0%)	0/87 (0.0%)
IAM	winterbaume-iam	awsQuery	154/176 (87.5%)	22/176 (12.5%)	119/176 (67.6%)	0/176 (0.0%)	39/176 (22.2%)
IAM Access Analyzer	winterbaume-accessanalyzer	restJson1	11/37 (29.7%)	0/37 (0.0%)	0/37 (0.0%)	0/37 (0.0%)	0/37 (0.0%)
IAM Roles Anywhere	winterbaume-rolesanywhere	restJson1	28/30 (93.3%)	2/30 (6.7%)	0/30 (0.0%)	0/30 (0.0%)	0/30 (0.0%)
Identity Store	winterbaume-identitystore	awsJson1.1	17/19 (89.5%)	0/19 (0.0%)	14/19 (73.7%)	0/19 (0.0%)	0/19 (0.0%)
Inspector2	winterbaume-inspector2	restJson1	49/75 (65.3%)	21/75 (28.0%)	19/75 (25.3%)	0/75 (0.0%)	0/75 (0.0%)
IoT	winterbaume-iot	restJson1	103/272 (37.9%)	0/272 (0.0%)	100/272 (36.8%)	0/272 (0.0%)	0/272 (0.0%)
IoT Data Plane	winterbaume-iotdataplane	restJson1	8/8 (100.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)
IVS	winterbaume-ivs	restJson1	30/40 (75.0%)	5/40 (12.5%)	6/40 (15.0%)	0/40 (0.0%)	0/40 (0.0%)
Keyspaces	winterbaume-keyspaces	awsJson1.0	19/19 (100.0%)	0/19 (0.0%)	0/19 (0.0%)	0/19 (0.0%)	0/19 (0.0%)
Kinesis	winterbaume-kinesis	awsJson1.1	38/39 (97.4%)	0/39 (0.0%)	31/39 (79.5%)	0/39 (0.0%)	9/39 (23.1%)
Kinesis Analytics V2	winterbaume-kinesisanalyticsv2	awsJson1.1	32/33 (97.0%)	1/33 (3.0%)	0/33 (0.0%)	0/33 (0.0%)	0/33 (0.0%)
Kinesis Video	winterbaume-kinesisvideo	restJson1	32/32 (100.0%)	0/32 (0.0%)	0/32 (0.0%)	0/32 (0.0%)	0/32 (0.0%)
Kinesis Video Archived Media	winterbaume-kinesisvideoarchivedmedia	restJson1	6/6 (100.0%)	0/6 (0.0%)	3/6 (50.0%)	0/6 (0.0%)	0/6 (0.0%)
KMS	winterbaume-kms	awsJson1.1	53/54 (98.1%)	0/54 (0.0%)	40/54 (74.1%)	0/54 (0.0%)	19/54 (35.2%)
Lake Formation	winterbaume-lakeformation	restJson1	19/61 (31.1%)	1/61 (1.6%)	20/61 (32.8%)	0/61 (0.0%)	0/61 (0.0%)
Lambda	winterbaume-lambda	restJson1	85/85 (100.0%)	0/85 (0.0%)	46/85 (54.1%)	0/85 (0.0%)	17/85 (20.0%)
Lex Models V2	winterbaume-lexmodelsv2	restJson1	58/107 (54.2%)	2/107 (1.9%)	17/107 (15.9%)	0/107 (0.0%)	0/107 (0.0%)
Macie2	winterbaume-macie2	restJson1	67/81 (82.7%)	14/81 (17.3%)	13/81 (16.0%)	0/81 (0.0%)	24/81 (29.6%)
Managed Blockchain	winterbaume-managedblockchain	restJson1	27/27 (100.0%)	0/27 (0.0%)	20/27 (74.1%)	0/27 (0.0%)	0/27 (0.0%)
Marketplace Metering	winterbaume-marketplacemetering	awsJson1.1	4/4 (100.0%)	0/4 (0.0%)	0/4 (0.0%)	0/4 (0.0%)	0/4 (0.0%)
MediaConnect	winterbaume-mediaconnect	restJson1	21/82 (25.6%)	0/82 (0.0%)	18/82 (22.0%)	0/82 (0.0%)	0/82 (0.0%)
MediaLive	winterbaume-medialive	restJson1	16/123 (13.0%)	0/123 (0.0%)	12/123 (9.8%)	0/123 (0.0%)	0/123 (0.0%)
MediaPackage	winterbaume-mediapackage	restJson1	9/19 (47.4%)	0/19 (0.0%)	9/19 (47.4%)	0/19 (0.0%)	0/19 (0.0%)
MediaPackage v2	winterbaume-mediapackagev2	restJson1	7/30 (23.3%)	0/30 (0.0%)	7/30 (23.3%)	0/30 (0.0%)	0/30 (0.0%)
MediaStore	winterbaume-mediastore	awsJson1.1	11/21 (52.4%)	0/21 (0.0%)	11/21 (52.4%)	0/21 (0.0%)	0/21 (0.0%)
MediaStore Data	winterbaume-mediastoredata	restJson1	5/5 (100.0%)	0/5 (0.0%)	4/5 (80.0%)	0/5 (0.0%)	0/5 (0.0%)
MemoryDB	winterbaume-memorydb	awsJson1.1	13/45 (28.9%)	0/45 (0.0%)	13/45 (28.9%)	0/45 (0.0%)	10/45 (22.2%)
MQ	winterbaume-mq	restJson1	23/24 (95.8%)	1/24 (4.2%)	19/24 (79.2%)	0/24 (0.0%)	6/24 (25.0%)
MSK	winterbaume-kafka	restJson1	10/59 (16.9%)	0/59 (0.0%)	13/59 (22.0%)	0/59 (0.0%)	6/59 (10.2%)
Neptune	winterbaume-neptune	awsQuery	64/70 (91.4%)	6/70 (8.6%)	47/70 (67.1%)	0/70 (0.0%)	6/70 (8.6%)
Network Firewall	winterbaume-networkfirewall	awsJson1.0	79/79 (100.0%)	0/79 (0.0%)	5/79 (6.3%)	0/79 (0.0%)	0/79 (0.0%)
Network Manager	winterbaume-networkmanager	restJson1	53/95 (55.8%)	0/95 (0.0%)	18/95 (18.9%)	0/95 (0.0%)	0/95 (0.0%)
OpenSearch	winterbaume-opensearch	restJson1	44/88 (50.0%)	0/88 (0.0%)	11/88 (12.5%)	0/88 (0.0%)	0/88 (0.0%)
OpenSearch Ingestion	winterbaume-osis	restJson1	10/22 (45.5%)	0/22 (0.0%)	13/22 (59.1%)	0/22 (0.0%)	0/22 (0.0%)
OpenSearch Serverless	winterbaume-opensearchserverless	awsJson1.0	12/46 (26.1%)	0/46 (0.0%)	12/46 (26.1%)	0/46 (0.0%)	0/46 (0.0%)
Organizations	winterbaume-organizations	awsJson1.1	60/63 (95.2%)	3/63 (4.8%)	41/63 (65.1%)	0/63 (0.0%)	11/63 (17.5%)
Outposts	winterbaume-outposts	restJson1	13/37 (35.1%)	0/37 (0.0%)	0/37 (0.0%)	0/37 (0.0%)	0/37 (0.0%)
Panorama	winterbaume-panorama	restJson1	10/34 (29.4%)	1/34 (2.9%)	11/34 (32.4%)	0/34 (0.0%)	0/34 (0.0%)
Performance Insights	winterbaume-pi	awsJson1.1	9/13 (69.2%)	4/13 (30.8%)	0/13 (0.0%)	0/13 (0.0%)	0/13 (0.0%)
Personalize	winterbaume-personalize	awsJson1.1	66/71 (93.0%)	5/71 (7.0%)	4/71 (5.6%)	0/71 (0.0%)	0/71 (0.0%)
Personalize Events	winterbaume-personalizeevents	restJson1	5/5 (100.0%)	0/5 (0.0%)	0/5 (0.0%)	0/5 (0.0%)	0/5 (0.0%)
Personalize Runtime	winterbaume-personalizeruntime	restJson1	3/3 (100.0%)	0/3 (0.0%)	0/3 (0.0%)	0/3 (0.0%)	0/3 (0.0%)
Pinpoint	winterbaume-pinpoint	restJson1	15/122 (12.3%)	0/122 (0.0%)	12/122 (9.8%)	0/122 (0.0%)	0/122 (0.0%)
Pinpoint SMS Voice	winterbaume-pinpointsmsvoice	restJson1	4/8 (50.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)	0/8 (0.0%)
Polly	winterbaume-polly	restJson1	9/10 (90.0%)	0/10 (0.0%)	5/10 (50.0%)	0/10 (0.0%)	0/10 (0.0%)
Pricing	winterbaume-pricing	awsJson1.1	5/5 (100.0%)	0/5 (0.0%)	0/5 (0.0%)	0/5 (0.0%)	0/5 (0.0%)
Private CA Connector for SCEP	winterbaume-pcaconnectorscep	restJson1	11/12 (91.7%)	0/12 (0.0%)	0/12 (0.0%)	0/12 (0.0%)	0/12 (0.0%)
QuickSight	winterbaume-quicksight	restJson1	68/232 (29.3%)	0/232 (0.0%)	31/232 (13.4%)	0/232 (0.0%)	0/232 (0.0%)
RAM	winterbaume-ram	restJson1	35/35 (100.0%)	0/35 (0.0%)	8/35 (22.9%)	0/35 (0.0%)	0/35 (0.0%)
RDS	winterbaume-rds	awsQuery	146/164 (89.0%)	4/164 (2.4%)	85/164 (51.8%)	0/164 (0.0%)	12/164 (7.3%)
RDS Data	winterbaume-rdsdata	restJson1	6/6 (100.0%)	0/6 (0.0%)	1/6 (16.7%)	0/6 (0.0%)	0/6 (0.0%)
Recycle Bin	winterbaume-rbin	restJson1	9/10 (90.0%)	0/10 (0.0%)	0/10 (0.0%)	0/10 (0.0%)	0/10 (0.0%)
Redshift	winterbaume-redshift	awsQuery	100/141 (70.9%)	3/141 (2.1%)	35/141 (24.8%)	0/141 (0.0%)	7/141 (5.0%)
Redshift Data	winterbaume-redshiftdata	awsJson1.1	11/11 (100.0%)	0/11 (0.0%)	4/11 (36.4%)	0/11 (0.0%)	0/11 (0.0%)
Rekognition	winterbaume-rekognition	awsJson1.1	8/75 (10.7%)	4/75 (5.3%)	8/75 (10.7%)	0/75 (0.0%)	13/75 (17.3%)
Resilience Hub	winterbaume-resiliencehub	restJson1	22/63 (34.9%)	0/63 (0.0%)	17/63 (27.0%)	0/63 (0.0%)	17/63 (27.0%)
Resource Groups	winterbaume-resourcegroups	restJson1	22/23 (95.7%)	1/23 (4.3%)	15/23 (65.2%)	0/23 (0.0%)	0/23 (0.0%)
Resource Groups Tagging	winterbaume-resourcegroupstagging	awsJson1.1	5/9 (55.6%)	0/9 (0.0%)	0/9 (0.0%)	0/9 (0.0%)	0/9 (0.0%)
Route 53	winterbaume-route53	restXml	71/71 (100.0%)	0/71 (0.0%)	30/71 (42.3%)	0/71 (0.0%)	10/71 (14.1%)
Route 53 Domains	winterbaume-route53domains	awsJson1.1	5/34 (14.7%)	0/34 (0.0%)	0/34 (0.0%)	0/34 (0.0%)	0/34 (0.0%)
Route 53 Recovery Cluster	winterbaume-route53recoverycluster	awsJson1.0	4/4 (100.0%)	0/4 (0.0%)	0/4 (0.0%)	0/4 (0.0%)	0/4 (0.0%)
Route 53 Resolver	winterbaume-route53resolver	awsJson1.1	28/68 (41.2%)	0/68 (0.0%)	28/68 (41.2%)	0/68 (0.0%)	11/68 (16.2%)
S3	winterbaume-s3	restXml	103/107 (96.3%)	4/107 (3.7%)	73/107 (68.2%)	51/107 (47.7%)	36/107 (33.6%)
S3 Control	winterbaume-s3control	restXml	87/97 (89.7%)	10/97 (10.3%)	0/97 (0.0%)	0/97 (0.0%)	7/97 (7.2%)
S3 Files	winterbaume-s3files	restJson1	21/21 (100.0%)	0/21 (0.0%)	0/21 (0.0%)	0/21 (0.0%)	0/21 (0.0%)
S3 on Outposts	winterbaume-s3outposts	restJson1	3/5 (60.0%)	1/5 (20.0%)	0/5 (0.0%)	0/5 (0.0%)	0/5 (0.0%)
S3 Tables	winterbaume-s3tables	restJson1	46/49 (93.9%)	3/49 (6.1%)	14/49 (28.6%)	0/49 (0.0%)	12/49 (24.5%)
S3 Vectors	winterbaume-s3vectors	restJson1	19/19 (100.0%)	0/19 (0.0%)	15/19 (78.9%)	0/19 (0.0%)	0/19 (0.0%)
SageMaker	winterbaume-sagemaker	awsJson1.1	141/396 (35.6%)	1/396 (0.3%)	112/396 (28.3%)	0/396 (0.0%)	11/396 (2.8%)
SageMaker Metrics	winterbaume-sagemakermetrics	restJson1	2/2 (100.0%)	0/2 (0.0%)	1/2 (50.0%)	0/2 (0.0%)	0/2 (0.0%)
SageMaker Runtime	winterbaume-sagemakerruntime	restJson1	3/3 (100.0%)	0/3 (0.0%)	2/3 (66.7%)	0/3 (0.0%)	0/3 (0.0%)
Savings Plans	winterbaume-savingsplans	restJson1	10/10 (100.0%)	0/10 (0.0%)	0/10 (0.0%)	0/10 (0.0%)	0/10 (0.0%)
Scheduler	winterbaume-scheduler	restJson1	12/12 (100.0%)	0/12 (0.0%)	12/12 (100.0%)	0/12 (0.0%)	9/12 (75.0%)
Secrets Manager	winterbaume-secretsmanager	awsJson1.1	22/23 (95.7%)	1/23 (4.3%)	21/23 (91.3%)	0/23 (0.0%)	11/23 (47.8%)
Security Hub	winterbaume-securityhub	restJson1	97/107 (90.7%)	10/107 (9.3%)	13/107 (12.1%)	0/107 (0.0%)	0/107 (0.0%)
Service Catalog	winterbaume-servicecatalog	awsJson1.1	4/90 (4.4%)	0/90 (0.0%)	0/90 (0.0%)	0/90 (0.0%)	0/90 (0.0%)
Service Catalog AppRegistry	winterbaume-servicecatalogappregistry	restJson1	23/24 (95.8%)	1/24 (4.2%)	0/24 (0.0%)	0/24 (0.0%)	0/24 (0.0%)
Service Discovery	winterbaume-servicediscovery	awsJson1.1	27/30 (90.0%)	0/30 (0.0%)	27/30 (90.0%)	0/30 (0.0%)	0/30 (0.0%)
Service Quotas	winterbaume-servicequotas	awsJson1.1	5/26 (19.2%)	0/26 (0.0%)	2/26 (7.7%)	0/26 (0.0%)	8/26 (30.8%)
SES v1	winterbaume-ses	awsQuery	38/71 (53.5%)	2/71 (2.8%)	38/71 (53.5%)	0/71 (0.0%)	0/71 (0.0%)
SES v2	winterbaume-sesv2	restJson1	106/110 (96.4%)	4/110 (3.6%)	28/110 (25.5%)	0/110 (0.0%)	9/110 (8.2%)
Shield	winterbaume-shield	awsJson1.1	9/36 (25.0%)	0/36 (0.0%)	9/36 (25.0%)	0/36 (0.0%)	0/36 (0.0%)
Signer	winterbaume-signer	restJson1	19/19 (100.0%)	0/19 (0.0%)	7/19 (36.8%)	0/19 (0.0%)	0/19 (0.0%)
SimpleDB v2	winterbaume-simpledbv2	restJson1	3/3 (100.0%)	0/3 (0.0%)	0/3 (0.0%)	0/3 (0.0%)	0/3 (0.0%)
SimSpace Weaver	winterbaume-simspaceweaver	restJson1	15/16 (93.8%)	0/16 (0.0%)	0/16 (0.0%)	0/16 (0.0%)	0/16 (0.0%)
Snow Device Management	winterbaume-snowdevicemanagement	restJson1	11/13 (84.6%)	0/13 (0.0%)	0/13 (0.0%)	0/13 (0.0%)	0/13 (0.0%)
SNS	winterbaume-sns	awsQuery	41/42 (97.6%)	1/42 (2.4%)	33/42 (78.6%)	0/42 (0.0%)	13/42 (31.0%)
SQS	winterbaume-sqs	awsJson1.0	23/23 (100.0%)	0/23 (0.0%)	20/23 (87.0%)	0/23 (0.0%)	14/23 (60.9%)
SSM	winterbaume-ssm	awsJson1.1	127/146 (87.0%)	19/146 (13.0%)	41/146 (28.1%)	0/146 (0.0%)	7/146 (4.8%)
SSM Quick Setup	winterbaume-ssmquicksetup	restJson1	6/14 (42.9%)	0/14 (0.0%)	0/14 (0.0%)	0/14 (0.0%)	0/14 (0.0%)
SSO	winterbaume-sso	restJson1	4/4 (100.0%)	0/4 (0.0%)	0/4 (0.0%)	0/4 (0.0%)	0/4 (0.0%)
SSO Admin	winterbaume-ssoadmin	awsJson1.1	27/79 (34.2%)	1/79 (1.3%)	25/79 (31.6%)	0/79 (0.0%)	0/79 (0.0%)
Step Functions	winterbaume-sfn	awsJson1.0	35/37 (94.6%)	2/37 (5.4%)	29/37 (78.4%)	0/37 (0.0%)	18/37 (48.6%)
STS	winterbaume-sts	awsQuery	11/11 (100.0%)	0/11 (0.0%)	7/11 (63.6%)	0/11 (0.0%)	6/11 (54.5%)
Support	winterbaume-support	awsJson1.1	5/16 (31.2%)	1/16 (6.2%)	5/16 (31.2%)	0/16 (0.0%)	0/16 (0.0%)
Support App	winterbaume-supportapp	restJson1	3/10 (30.0%)	0/10 (0.0%)	0/10 (0.0%)	0/10 (0.0%)	0/10 (0.0%)
SWF	winterbaume-swf	awsJson1.0	30/39 (76.9%)	0/39 (0.0%)	19/39 (48.7%)	0/39 (0.0%)	0/39 (0.0%)
Synthetics	winterbaume-synthetics	restJson1	22/22 (100.0%)	0/22 (0.0%)	4/22 (18.2%)	0/22 (0.0%)	0/22 (0.0%)
Tax Settings	winterbaume-taxsettings	restJson1	0/16 (0.0%)	0/16 (0.0%)	0/16 (0.0%)	0/16 (0.0%)	0/16 (0.0%)
Textract	winterbaume-textract	awsJson1.1	6/25 (24.0%)	0/25 (0.0%)	5/25 (20.0%)	0/25 (0.0%)	0/25 (0.0%)
Timestream InfluxDB	winterbaume-timestreaminfluxdb	awsJson1.0	19/19 (100.0%)	0/19 (0.0%)	13/19 (68.4%)	0/19 (0.0%)	0/19 (0.0%)
Timestream Query	winterbaume-timestreamquery	awsJson1.0	15/15 (100.0%)	0/15 (0.0%)	6/15 (40.0%)	0/15 (0.0%)	0/15 (0.0%)
Timestream Write	winterbaume-timestreamwrite	awsJson1.0	19/19 (100.0%)	0/19 (0.0%)	15/19 (78.9%)	0/19 (0.0%)	0/19 (0.0%)
Transcribe	winterbaume-transcribe	awsJson1.1	16/43 (37.2%)	0/43 (0.0%)	16/43 (37.2%)	0/43 (0.0%)	0/43 (0.0%)
Transfer	winterbaume-transfer	awsJson1.1	44/71 (62.0%)	0/71 (0.0%)	14/71 (19.7%)	0/71 (0.0%)	0/71 (0.0%)
Trusted Advisor	winterbaume-trustedadvisor	restJson1	6/11 (54.5%)	4/11 (36.4%)	0/11 (0.0%)	0/11 (0.0%)	0/11 (0.0%)
VPC Lattice	winterbaume-vpclattice	restJson1	66/73 (90.4%)	2/73 (2.7%)	35/73 (47.9%)	0/73 (0.0%)	0/73 (0.0%)
WAFv2	winterbaume-wafv2	awsJson1.1	38/55 (69.1%)	0/55 (0.0%)	29/55 (52.7%)	0/55 (0.0%)	0/55 (0.0%)
WorkSpaces	winterbaume-workspaces	awsJson1.1	50/91 (54.9%)	0/91 (0.0%)	16/91 (17.6%)	0/91 (0.0%)	0/91 (0.0%)
WorkSpaces Web	winterbaume-workspacesweb	restJson1	68/75 (90.7%)	0/75 (0.0%)	27/75 (36.0%)	0/75 (0.0%)	0/75 (0.0%)
X-Ray	winterbaume-xray	restJson1	34/38 (89.5%)	4/38 (10.5%)	0/38 (0.0%)	0/38 (0.0%)	6/38 (15.8%)

winterbaume: 7210 / 11367 operations across 224 services (63.4%)

winterbaume stubs: 326 / 11367 operations across 224 services (2.9%) - routed but return empty/default responses

moto: 3302 / 11367 operations across 224 services (29.0%)

floci: 160 / 11367 operations across 224 services (1.4%)

kumo: 790 / 11367 operations across 224 services (6.9%)

Terraform State Converter Coverage

Winterbaume includes a Terraform state converter layer (winterbaume-terraform) that can inject Terraform state into the emulator and extract it back. This enables seeding mock environments from existing Terraform state files, and round-tripping state for validation.

267 Terraform resource types across 137 services are supported, covering 67.4% of inject attributes and 59.7% of extract attributes against the official Terraform AWS provider schema.

Rating	Count	Criteria
Excellent	265	inject >= 60% AND extract >= 50%
Good	0	inject >= 40% OR extract >= 30%
N/A	2	No TF provider schema entry

See the full Terraform converter coverage report for per-resource details.

Usage

Library mode (in-process)

use winterbaume_core::MockAws;
use winterbaume_sts::StsService;
use winterbaume_iam::IamService;
use winterbaume_s3::S3Service;

let mock = MockAws::builder()
    .with_service(StsService::new())
    .with_service(IamService::new())
    .with_service(S3Service::new())
    .build();

let config = aws_config::defaults(BehaviorVersion::latest())
    .http_client(mock.http_client())
    .credentials_provider(mock.credentials_provider())
    .region("us-east-1")
    .load()
    .await;

let sts = aws_sdk_sts::Client::new(&config);
let resp = sts.get_caller_identity().send().await.unwrap();
assert_eq!(resp.account(), Some("123456789012"));

Standalone HTTP server

For non-Rust clients, winterbaume-server provides a standalone HTTP server:

cargo run -p winterbaume-server -- --host 127.0.0.1 --port 5555

Point the AWS SDK at it:

export AWS_ENDPOINT_URL=http://localhost:5555
aws s3 mb s3://my-bucket

Architecture

• winterbaume-core -- shared infrastructure: MockAws builder, MockService trait, per-account/region state management, HTTP client/connector bridge.
• winterbaume-{service} -- each service crate implements MockService with its own protocol handling and in-memory state.
• winterbaume-server -- hyper-based HTTP server that registers all service backends.

State is partitioned per account ID and region, matching real AWS isolation semantics.

FAQ

What is the difference between Winterbaume and moto?

Winterbaume targets the Rust AWS SDK directly. It provides an in-process HTTP client for aws-sdk-rust, so tests can run without standing up an external mock service. The project also tracks moto coverage and behaviour closely, and vendors moto as a reference implementation.

When should I use library mode instead of the standalone server?

Use library mode when you are writing Rust tests against aws-sdk-rust and want the fastest setup with no network I/O. Use winterbaume-server when you need to point non-Rust clients, CLIs, or external processes at a mock AWS endpoint over HTTP.

What is the difference between an operation and a stub?

The Operations column counts handlers with real, state-backed logic: they parse the request, mutate or query the in-memory backend state, validate inputs, and produce an AWS-shaped response. The Stubs column counts handlers that route the request and immediately return an empty or default response without consulting state. Stubs are still useful for keeping SDK calls from erroring out ( e.g. callers that issue a Describe* operation purely as a precondition check ), but they will not reflect any prior Create* or Update* you made on the same mock. Stubs are either annotated explicitly with // STUB[<category>]: <reason> in the handler source, or detected heuristically by the coverage script when the body is short and free of state access.

What happens if an operation is not implemented yet?

If the operation appears in the Operations column it has real behaviour. If it appears in the Stubs column it returns an empty or default response and does not interact with state. If it appears in neither column the request is unrouted and the service returns a 501-style "not implemented" error.

Why are there so many stubs?

Some AWS APIs depend on infrastructure that does not exist inside an emulator: instance telemetry ( EC2 monitoring, CPU credit specs ), real-time message delivery, multi-account Organizations integration, billing pipelines, etc. Rather than fail noisily on these calls, winterbaume returns an empty default so a workflow that touches them as part of a larger setup does not break. The stub count is shown next to every service so you can assess this trade-off before depending on a particular call.

Does Winterbaume keep state between requests?

Yes. State is stored in memory and isolated by account ID and region so repeated SDK calls can observe changes made by earlier requests in the same mock environment.

What is Winterbaume named after?

It is a multilingual pun built around the reference project name moto. "Winter tree" is the literal reading, but the real joke is the sound and imagery of a Japanese pop-culture name hiding in plain sight.

Limitations

The following are known limitations of the current implementation.

Partial operation coverage for some services. Several service crates cover only a subset of the total API surface. Unimplemented operations return 501 Not Implemented. The coverage table above shows the exact count for each service.

No real execution engines for compute-style operations. Operations that require an actual evaluation engine — such as Change Calendar evaluation, SSM Automation execution, or Bedrock model invocation — are marked STUB[no-engine] and return plausible empty or default responses rather than computed results.

No real telemetry-driven responses. Operations whose responses depend on live infrastructure metrics or access histories — for example, IAM credential report generation or patch compliance queries — are marked STUB[no-telemetry] and return synthetic or empty data.

Cross-account and AWS Organizations integration is limited. Operations that require real AWS Organizations cross-account state (member accounts, SCPs, delegated administrators) are marked STUB[org-integration] and return minimal responses. The mock environment is single-account by default.

No persistence across server restarts. All state is stored in process memory. Stopping winterbaume-server (or dropping a MockAws instance) discards all resources. Durable persistence for services such as SSM Parameter Store or Secrets Manager is a known open item.

Athena-Glue catalogue integration is not wired. In real AWS, Athena's default data catalogue is the Glue Data Catalogue. Winterbaume accepts DataCatalogType::Glue at the CRUD level but does not resolve Glue-managed table metadata during query execution. SQL queries against Glue-backed catalogues will not see schema from the mock Glue state.

IAM policy simulation fidelity is incomplete. SimulateCustomPolicy and SimulatePrincipalPolicy use winterbaume-iam-rule-eval, which covers allow, explicit deny, and implicit deny paths. However, richer condition key resolution, permissions boundaries, and full principal-context matching are not yet at full AWS parity.

StatefulService::snapshot() is non-fallible. Blob read failures (for example, from S3, EBS, or Glacier large-object payloads) are logged but cannot be returned as errors to the caller. State snapshots that encounter blob read failures will be incomplete rather than returning an error.

Partial rpc-v2-cbor serialisation coverage. CloudWatch uses the rpc-v2-cbor protocol. Typed output serialisers do not yet cover every timestamp shape the SDK expects, particularly list-of-timestamp paths that require Tag 1-aware response shaping.

Cross-service integrations follow documented AWS seams only. Behaviour that couples one AWS service to another (Lambda event sources, EventBridge targets, Step Functions optimised integrations, AppSync data sources) is modelled on documented AWS contracts. Ad hoc or undocumented cross-service interactions are not emulated.

License

Apache-2.0. See LICENSE for the full text.

This project uses moto (Copyright 2012 Steve Pulec, Apache-2.0) as a reference implementation. See NOTICE for third-party attribution details.