ministack 1.1.1

Free, open-source local AWS emulator — drop-in LocalStack replacement

MiniStack — Free, Open-Source Local AWS Emulator

LocalStack is no longer free. MiniStack is a fully open-source, zero-cost drop-in replacement. Single port · No account · No license key · No telemetry · Just AWS APIs, locally.

---

Why MiniStack?

LocalStack recently moved its core services behind a paid plan. If you relied on LocalStack Community for local development and CI/CD pipelines, MiniStack is your free alternative.

• 26 AWS services emulated on a single port (4566)
• Drop-in compatible — works with boto3, AWS CLI, Terraform, CDK, Pulumi, any SDK
• Real infrastructure — RDS spins up actual Postgres/MySQL containers, ElastiCache spins up real Redis, Athena runs real SQL via DuckDB, ECS runs real Docker containers
• Tiny footprint — ~150MB image, ~30MB RAM at idle vs LocalStack's ~1GB image and ~500MB RAM
• Fast startup — under 2 seconds
• MIT licensed — use it, fork it, contribute to it

---

Quick Start

# Option 1: PyPI (simplest)
pip install ministack
ministack
# Runs on http://localhost:4566 — use GATEWAY_PORT=XXXX to change

# Option 2: Docker Hub
docker run -p 4566:4566 nahuelnucera/ministack

# Option 3: Clone and build
git clone https://github.com/Nahuel990/ministack
cd ministack
docker compose up -d

# Verify (any option)
curl http://localhost:4566/_localstack/health

That's it. No account, no API key, no sign-up.

---

Using with AWS CLI

# Option A — environment variables (no profile needed)
export AWS_ACCESS_KEY_ID=test
export AWS_SECRET_ACCESS_KEY=test
export AWS_DEFAULT_REGION=us-east-1

aws --endpoint-url=http://localhost:4566 s3 mb s3://my-bucket
aws --endpoint-url=http://localhost:4566 sqs create-queue --queue-name my-queue
aws --endpoint-url=http://localhost:4566 dynamodb list-tables
aws --endpoint-url=http://localhost:4566 sts get-caller-identity

# Option B — named profile (must pass --profile on every command)
aws configure --profile local
# AWS Access Key ID: test
# AWS Secret Access Key: test
# Default region: us-east-1
# Default output format: json

aws --profile local --endpoint-url=http://localhost:4566 s3 mb s3://my-bucket
aws --profile local --endpoint-url=http://localhost:4566 s3 cp ./file.txt s3://my-bucket/
aws --profile local --endpoint-url=http://localhost:4566 sqs create-queue --queue-name my-queue
aws --profile local --endpoint-url=http://localhost:4566 dynamodb list-tables
aws --profile local --endpoint-url=http://localhost:4566 sts get-caller-identity

awslocal wrapper

chmod +x bin/awslocal
./bin/awslocal s3 ls
./bin/awslocal dynamodb list-tables

---

Using with boto3

import boto3

# All clients use the same endpoint
def client(service):
    return boto3.client(
        service,
        endpoint_url="http://localhost:4566",
        aws_access_key_id="test",
        aws_secret_access_key="test",
        region_name="us-east-1",
    )

# S3
s3 = client("s3")
s3.create_bucket(Bucket="my-bucket")
s3.put_object(Bucket="my-bucket", Key="hello.txt", Body=b"Hello, MiniStack!")
obj = s3.get_object(Bucket="my-bucket", Key="hello.txt")
print(obj["Body"].read())  # b'Hello, MiniStack!'

# SQS
sqs = client("sqs")
q = sqs.create_queue(QueueName="my-queue")
sqs.send_message(QueueUrl=q["QueueUrl"], MessageBody="hello")
msgs = sqs.receive_message(QueueUrl=q["QueueUrl"])
print(msgs["Messages"][0]["Body"])  # hello

# DynamoDB
ddb = client("dynamodb")
ddb.create_table(
    TableName="Users",
    KeySchema=[{"AttributeName": "userId", "KeyType": "HASH"}],
    AttributeDefinitions=[{"AttributeName": "userId", "AttributeType": "S"}],
    BillingMode="PAY_PER_REQUEST",
)
ddb.put_item(TableName="Users", Item={"userId": {"S": "u1"}, "name": {"S": "Alice"}})

# SSM Parameter Store
ssm = client("ssm")
ssm.put_parameter(Name="/app/db/host", Value="localhost", Type="String")
param = ssm.get_parameter(Name="/app/db/host")
print(param["Parameter"]["Value"])  # localhost

# Secrets Manager
sm = client("secretsmanager")
sm.create_secret(Name="db-password", SecretString='{"password":"s3cr3t"}')

# Kinesis
kin = client("kinesis")
kin.create_stream(StreamName="events", ShardCount=1)
kin.put_record(StreamName="events", Data=b'{"event":"click"}', PartitionKey="user1")

# EventBridge
eb = client("events")
eb.put_events(Entries=[{
    "Source": "myapp",
    "DetailType": "UserSignup",
    "Detail": '{"userId": "123"}',
    "EventBusName": "default",
}])

# Step Functions
sfn = client("stepfunctions")
sfn.create_state_machine(
    name="my-workflow",
    definition='{"StartAt":"Hello","States":{"Hello":{"Type":"Pass","End":true}}}',
    roleArn="arn:aws:iam::000000000000:role/role",
)

# EC2
ec2 = client("ec2")
reservation = ec2.run_instances(
    ImageId="ami-00000001",
    MinCount=1,
    MaxCount=1,
    InstanceType="t3.micro",
)
instance_id = reservation["Instances"][0]["InstanceId"]
print(instance_id)  # i-xxxxxxxxxxxxxxxxx

# Security Groups
sg = ec2.create_security_group(GroupName="my-sg", Description="My SG")
ec2.authorize_security_group_ingress(
    GroupId=sg["GroupId"],
    IpPermissions=[{"IpProtocol": "tcp", "FromPort": 80, "ToPort": 80,
                    "IpRanges": [{"CidrIp": "0.0.0.0/0"}]}],
)

# VPC / Subnet
vpc = ec2.create_vpc(CidrBlock="10.0.0.0/16")
subnet = ec2.create_subnet(
    VpcId=vpc["Vpc"]["VpcId"],
    CidrBlock="10.0.1.0/24",
    AvailabilityZone="us-east-1a",
)

---

Supported Services

Core Services

Service	Operations	Notes
S3	CreateBucket, DeleteBucket, ListBuckets, HeadBucket, PutObject, GetObject, DeleteObject, HeadObject, CopyObject, ListObjects v1/v2, DeleteObjects, GetBucketVersioning, PutBucketVersioning, GetBucketEncryption, PutBucketEncryption, DeleteBucketEncryption, GetBucketLifecycleConfiguration, PutBucketLifecycleConfiguration, DeleteBucketLifecycle, GetBucketCors, PutBucketCors, DeleteBucketCors, GetBucketAcl, PutBucketAcl, GetBucketTagging, PutBucketTagging, DeleteBucketTagging, GetBucketPolicy, PutBucketPolicy, DeleteBucketPolicy, GetBucketNotificationConfiguration, PutBucketNotificationConfiguration, GetBucketLogging, PutBucketLogging, ListObjectVersions, CreateMultipartUpload, UploadPart, CompleteMultipartUpload, AbortMultipartUpload	Optional disk persistence via S3_PERSIST=1
SQS	CreateQueue, DeleteQueue, ListQueues, GetQueueUrl, GetQueueAttributes, SetQueueAttributes, PurgeQueue, SendMessage, ReceiveMessage, DeleteMessage, ChangeMessageVisibility, ChangeMessageVisibilityBatch, SendMessageBatch, DeleteMessageBatch, TagQueue, UntagQueue, ListQueueTags	Both Query API and JSON protocol; FIFO queues with deduplication; DLQ support
SNS	CreateTopic, DeleteTopic, ListTopics, GetTopicAttributes, SetTopicAttributes, Subscribe, Unsubscribe, ListSubscriptions, ListSubscriptionsByTopic, GetSubscriptionAttributes, SetSubscriptionAttributes, ConfirmSubscription, Publish, PublishBatch, TagResource, UntagResource, ListTagsForResource, CreatePlatformApplication, CreatePlatformEndpoint	SNS→SQS fanout delivery; SNS→Lambda fanout (synchronous invocation)
DynamoDB	CreateTable, UpdateTable, DeleteTable, DescribeTable, ListTables, PutItem, GetItem, DeleteItem, UpdateItem, Query, Scan, BatchWriteItem, BatchGetItem, TransactWriteItems, TransactGetItems, DescribeTimeToLive, UpdateTimeToLive, DescribeContinuousBackups, UpdateContinuousBackups, DescribeEndpoints, TagResource, UntagResource, ListTagsOfResource	TTL enforced via thread-safe background reaper (60s cadence)
Lambda	CreateFunction, DeleteFunction, GetFunction, ListFunctions, Invoke, UpdateFunctionCode, UpdateFunctionConfiguration, AddPermission, RemovePermission, ListVersionsByFunction, PublishVersion, TagResource, UntagResource, ListTags, CreateEventSourceMapping, DeleteEventSourceMapping, GetEventSourceMapping, ListEventSourceMappings, UpdateEventSourceMapping, CreateFunctionUrlConfig, GetFunctionUrlConfig, UpdateFunctionUrlConfig, DeleteFunctionUrlConfig, ListFunctionUrlConfigs	Python runtimes actually execute with warm worker pool; SQS event source mapping; Function URL CRUD
IAM	CreateUser, GetUser, ListUsers, DeleteUser, CreateRole, GetRole, ListRoles, DeleteRole, CreatePolicy, GetPolicy, DeletePolicy, AttachRolePolicy, DetachRolePolicy, PutRolePolicy, GetRolePolicy, DeleteRolePolicy, ListRolePolicies, ListAttachedRolePolicies, CreateAccessKey, ListAccessKeys, DeleteAccessKey, CreateInstanceProfile, GetInstanceProfile, DeleteInstanceProfile, AddRoleToInstanceProfile, RemoveRoleFromInstanceProfile, ListInstanceProfiles, CreateGroup, GetGroup, AddUserToGroup, RemoveUserFromGroup, CreateServiceLinkedRole, CreateOpenIDConnectProvider, TagRole, UntagRole, TagUser, UntagUser, TagPolicy, UntagPolicy
STS	GetCallerIdentity, AssumeRole, GetSessionToken
SecretsManager	CreateSecret, GetSecretValue, ListSecrets, DeleteSecret, UpdateSecret, DescribeSecret, PutSecretValue, RestoreSecret, RotateSecret, GetRandomPassword, ListSecretVersionIds, TagResource, UntagResource, PutResourcePolicy, GetResourcePolicy, DeleteResourcePolicy, ValidateResourcePolicy
CloudWatch Logs	CreateLogGroup, DeleteLogGroup, DescribeLogGroups, CreateLogStream, DeleteLogStream, DescribeLogStreams, PutLogEvents, GetLogEvents, FilterLogEvents, PutRetentionPolicy, DeleteRetentionPolicy, PutSubscriptionFilter, DeleteSubscriptionFilter, DescribeSubscriptionFilters, PutMetricFilter, DeleteMetricFilter, DescribeMetricFilters, TagLogGroup, UntagLogGroup, ListTagsLogGroup, TagResource, UntagResource, ListTagsForResource, StartQuery, GetQueryResults, StopQuery, PutDestination, DeleteDestination, DescribeDestinations	FilterLogEvents supports */? globs, multi-term AND, -term exclusion

Extended Services

Service	Operations	Notes
SSM Parameter Store	PutParameter, GetParameter, GetParameters, GetParametersByPath, DeleteParameter, DeleteParameters, DescribeParameters, GetParameterHistory, LabelParameterVersion, AddTagsToResource, RemoveTagsFromResource, ListTagsForResource	Supports String, SecureString, StringList
EventBridge	CreateEventBus, DeleteEventBus, ListEventBuses, PutRule, DeleteRule, ListRules, DescribeRule, EnableRule, DisableRule, PutTargets, RemoveTargets, ListTargetsByRule, PutEvents, TagResource, UntagResource, ListTagsForResource, CreateArchive, DeleteArchive, DescribeArchive, ListArchives, PutPermission, RemovePermission, CreateConnection, DescribeConnection, DeleteConnection, ListConnections, CreateApiDestination, DescribeApiDestination, DeleteApiDestination, ListApiDestinations	Lambda target dispatch on PutEvents
Kinesis	CreateStream, DeleteStream, DescribeStream, ListStreams, ListShards, PutRecord, PutRecords, GetShardIterator, GetRecords, MergeShards, SplitShard, UpdateShardCount, StartStreamEncryption, StopStreamEncryption, EnableEnhancedMonitoring, DisableEnhancedMonitoring, RegisterStreamConsumer, DeregisterStreamConsumer, ListStreamConsumers, DescribeStreamConsumer, AddTagsToStream, RemoveTagsFromStream, ListTagsForStream	Partition key → shard routing
CloudWatch Metrics	PutMetricData, GetMetricStatistics, GetMetricData, ListMetrics, PutMetricAlarm, PutCompositeAlarm, DescribeAlarms, DescribeAlarmsForMetric, DescribeAlarmHistory, DeleteAlarms, SetAlarmState, EnableAlarmActions, DisableAlarmActions, TagResource, UntagResource, ListTagsForResource, PutDashboard, GetDashboard, DeleteDashboards, ListDashboards	CBOR and JSON protocol
SES	SendEmail, SendRawEmail, SendTemplatedEmail, SendBulkTemplatedEmail, VerifyEmailIdentity, VerifyEmailAddress, VerifyDomainIdentity, VerifyDomainDkim, ListIdentities, GetIdentityVerificationAttributes, GetIdentityDkimAttributes, DeleteIdentity, GetSendQuota, GetSendStatistics, CreateConfigurationSet, DeleteConfigurationSet, DescribeConfigurationSet, ListConfigurationSets, CreateTemplate, GetTemplate, UpdateTemplate, DeleteTemplate, ListTemplates	Emails stored in-memory, not sent
Step Functions	CreateStateMachine, DeleteStateMachine, DescribeStateMachine, UpdateStateMachine, ListStateMachines, StartExecution, StartSyncExecution, StopExecution, DescribeExecution, DescribeStateMachineForExecution, ListExecutions, GetExecutionHistory, SendTaskSuccess, SendTaskFailure, SendTaskHeartbeat, CreateActivity, DeleteActivity, DescribeActivity, ListActivities, GetActivityTask, TagResource, UntagResource, ListTagsForResource	Full ASL interpreter; Retry/Catch; waitForTaskToken; Activities (worker pattern); Pass/Task/Choice/Wait/Succeed/Fail/Map/Parallel
API Gateway v2	CreateApi, GetApi, GetApis, UpdateApi, DeleteApi, CreateRoute, GetRoute, GetRoutes, UpdateRoute, DeleteRoute, CreateIntegration, GetIntegration, GetIntegrations, UpdateIntegration, DeleteIntegration, CreateStage, GetStage, GetStages, UpdateStage, DeleteStage, CreateDeployment, GetDeployment, GetDeployments, DeleteDeployment, CreateAuthorizer, GetAuthorizer, GetAuthorizers, UpdateAuthorizer, DeleteAuthorizer, TagResource, UntagResource, GetTags	HTTP API (v2) protocol; Lambda proxy (AWS_PROXY) and HTTP proxy (HTTP_PROXY) integrations; data plane via {apiId}.execute-api.localhost; {param} and {proxy+} path matching; JWT/Lambda authorizer CRUD
API Gateway v1	CreateRestApi, GetRestApi, GetRestApis, UpdateRestApi, DeleteRestApi, CreateResource, GetResource, GetResources, UpdateResource, DeleteResource, PutMethod, GetMethod, DeleteMethod, UpdateMethod, PutMethodResponse, GetMethodResponse, DeleteMethodResponse, PutIntegration, GetIntegration, DeleteIntegration, UpdateIntegration, PutIntegrationResponse, GetIntegrationResponse, DeleteIntegrationResponse, CreateDeployment, GetDeployment, GetDeployments, UpdateDeployment, DeleteDeployment, CreateStage, GetStage, GetStages, UpdateStage, DeleteStage, CreateAuthorizer, GetAuthorizer, GetAuthorizers, UpdateAuthorizer, DeleteAuthorizer, CreateModel, GetModel, GetModels, DeleteModel, CreateApiKey, GetApiKey, GetApiKeys, UpdateApiKey, DeleteApiKey, CreateUsagePlan, GetUsagePlan, GetUsagePlans, UpdateUsagePlan, DeleteUsagePlan, CreateUsagePlanKey, GetUsagePlanKeys, DeleteUsagePlanKey, CreateDomainName, GetDomainName, GetDomainNames, DeleteDomainName, CreateBasePathMapping, GetBasePathMapping, GetBasePathMappings, DeleteBasePathMapping, TagResource, UntagResource, GetTags	REST API (v1) protocol; Lambda proxy format 1.0 (AWS_PROXY), HTTP proxy (HTTP_PROXY), MOCK integration; data plane via {apiId}.execute-api.localhost; resource tree with {param} and {proxy+} path matching; JSON Patch for all PATCH operations; state persistence

Infrastructure Services (with real Docker execution)

Service	Operations	Real Execution
ECS	CreateCluster, UpdateCluster, DeleteCluster, DescribeClusters, ListClusters, RegisterTaskDefinition, DeregisterTaskDefinition, DescribeTaskDefinition, ListTaskDefinitions, CreateService, DeleteService, DescribeServices, UpdateService, ListServices, RunTask, StopTask, DescribeTasks, ListTasks, CreateCapacityProvider, DeleteCapacityProvider, DescribeCapacityProviders, PutClusterCapacityProviders, TagResource, UntagResource, ListTagsForResource	RunTask starts real Docker containers via Docker socket
RDS	CreateDBInstance, DeleteDBInstance, DescribeDBInstances, StartDBInstance, StopDBInstance, RebootDBInstance, ModifyDBInstance, CreateDBCluster, DeleteDBCluster, DescribeDBClusters, StartDBCluster, StopDBCluster, CreateDBSubnetGroup, DescribeDBSubnetGroups, ModifyDBSubnetGroup, DeleteDBSubnetGroup, CreateDBParameterGroup, DescribeDBParameterGroups, ModifyDBParameterGroup, DeleteDBParameterGroup, DescribeDBParameters, CreateDBClusterParameterGroup, DescribeDBEngineVersions, DescribeOrderableDBInstanceOptions, CreateDBSnapshot, DeleteDBSnapshot, DescribeDBSnapshots, CreateDBClusterSnapshot, DeleteDBClusterSnapshot, DescribeDBClusterSnapshots, CreateDBInstanceReadReplica, RestoreDBInstanceFromDBSnapshot, CreateOptionGroup, DescribeOptionGroups, AddTagsToResource, RemoveTagsFromResource, ListTagsForResource	CreateDBInstance spins up real Postgres/MySQL Docker container, returns actual host:port endpoint
ElastiCache	CreateCacheCluster, DeleteCacheCluster, DescribeCacheClusters, ModifyCacheCluster, RebootCacheCluster, CreateReplicationGroup, DeleteReplicationGroup, DescribeReplicationGroups, ModifyReplicationGroup, IncreaseReplicaCount, DecreaseReplicaCount, CreateCacheSubnetGroup, DescribeCacheSubnetGroups, ModifyCacheSubnetGroup, DeleteCacheSubnetGroup, CreateCacheParameterGroup, DescribeCacheParameterGroups, ModifyCacheParameterGroup, ResetCacheParameterGroup, DeleteCacheParameterGroup, DescribeCacheParameters, DescribeCacheEngineVersions, CreateUser, DescribeUsers, DeleteUser, ModifyUser, CreateUserGroup, DescribeUserGroups, DeleteUserGroup, ModifyUserGroup, CreateSnapshot, DeleteSnapshot, DescribeSnapshots, DescribeEvents	CreateCacheCluster spins up real Redis/Memcached Docker container
Glue	CreateDatabase, DeleteDatabase, GetDatabase, GetDatabases, CreateTable, DeleteTable, GetTable, GetTables, UpdateTable, BatchDeleteTable, CreatePartition, GetPartitions, BatchCreatePartition, BatchGetPartition, CreatePartitionIndex, GetPartitionIndexes, CreateConnection, GetConnections, CreateCrawler, UpdateCrawler, GetCrawler, GetCrawlerMetrics, StartCrawler, CreateJob, GetJob, GetJobs, StartJobRun, GetJobRun, GetJobRuns, CreateTrigger, GetTrigger, DeleteTrigger, UpdateTrigger, StartTrigger, StopTrigger, ListTriggers, GetTriggers, CreateWorkflow, GetWorkflow, DeleteWorkflow, UpdateWorkflow, StartWorkflowRun, CreateSecurityConfiguration, GetSecurityConfiguration, GetSecurityConfigurations, DeleteSecurityConfiguration, CreateClassifier, GetClassifier, GetClassifiers, DeleteClassifier, TagResource, UntagResource, GetTags	Python shell jobs actually execute via subprocess
Athena	StartQueryExecution, GetQueryExecution, GetQueryResults, StopQueryExecution, ListQueryExecutions, BatchGetQueryExecution, CreateWorkGroup, DeleteWorkGroup, GetWorkGroup, ListWorkGroups, UpdateWorkGroup, CreateNamedQuery, DeleteNamedQuery, GetNamedQuery, ListNamedQueries, BatchGetNamedQuery, CreateDataCatalog, GetDataCatalog, ListDataCatalogs, DeleteDataCatalog, UpdateDataCatalog, CreatePreparedStatement, GetPreparedStatement, DeletePreparedStatement, ListPreparedStatements, GetTableMetadata, ListTableMetadata, TagResource, UntagResource, ListTagsForResource	Real SQL via DuckDB when installed (pip install duckdb), otherwise returns mock results; result pagination; column type metadata
Firehose	CreateDeliveryStream, DeleteDeliveryStream, DescribeDeliveryStream, ListDeliveryStreams, PutRecord, PutRecordBatch, UpdateDestination, TagDeliveryStream, UntagDeliveryStream, ListTagsForDeliveryStream, StartDeliveryStreamEncryption, StopDeliveryStreamEncryption	S3 destinations write records to the local S3 emulator; all other destination types buffer in-memory; concurrency-safe UpdateDestination via VersionId
Route53	CreateHostedZone, GetHostedZone, DeleteHostedZone, ListHostedZones, ListHostedZonesByName, UpdateHostedZoneComment, ChangeResourceRecordSets (CREATE/UPSERT/DELETE), ListResourceRecordSets, GetChange, CreateHealthCheck, GetHealthCheck, DeleteHealthCheck, ListHealthChecks, UpdateHealthCheck, ChangeTagsForResource, ListTagsForResource	REST/XML protocol; SOA + NS records auto-created; CallerReference idempotency; alias records, weighted/failover/latency routing; marker-based pagination
EC2	RunInstances, DescribeInstances, TerminateInstances, StopInstances, StartInstances, RebootInstances, DescribeImages, CreateSecurityGroup, DeleteSecurityGroup, DescribeSecurityGroups, AuthorizeSecurityGroupIngress, RevokeSecurityGroupIngress, AuthorizeSecurityGroupEgress, RevokeSecurityGroupEgress, CreateKeyPair, DeleteKeyPair, DescribeKeyPairs, ImportKeyPair, CreateVpc, DeleteVpc, DescribeVpcs, ModifyVpcAttribute, CreateSubnet, DeleteSubnet, DescribeSubnets, ModifySubnetAttribute, CreateInternetGateway, DeleteInternetGateway, DescribeInternetGateways, AttachInternetGateway, DetachInternetGateway, CreateRouteTable, DeleteRouteTable, DescribeRouteTables, AssociateRouteTable, DisassociateRouteTable, CreateRoute, ReplaceRoute, DeleteRoute, CreateNetworkInterface, DeleteNetworkInterface, DescribeNetworkInterfaces, AttachNetworkInterface, DetachNetworkInterface, CreateVpcEndpoint, DeleteVpcEndpoints, DescribeVpcEndpoints, DescribeAvailabilityZones, AllocateAddress, ReleaseAddress, AssociateAddress, DisassociateAddress, DescribeAddresses, CreateTags, DeleteTags, DescribeTags	In-memory state only — no real VMs; default VPC, subnet, security group, internet gateway, and route table always present; rules stored but not enforced (matches LocalStack)
Cognito	User Pools: CreateUserPool, DeleteUserPool, DescribeUserPool, ListUserPools, UpdateUserPool, CreateUserPoolClient, DeleteUserPoolClient, DescribeUserPoolClient, ListUserPoolClients, UpdateUserPoolClient, AdminCreateUser, AdminDeleteUser, AdminGetUser, ListUsers, AdminSetUserPassword, AdminUpdateUserAttributes, AdminConfirmSignUp, AdminDisableUser, AdminEnableUser, AdminResetUserPassword, AdminUserGlobalSignOut, AdminAddUserToGroup, AdminRemoveUserFromGroup, AdminListGroupsForUser, AdminListUserAuthEvents, AdminInitiateAuth, AdminRespondToAuthChallenge, InitiateAuth, RespondToAuthChallenge, GlobalSignOut, RevokeToken, SignUp, ConfirmSignUp, ForgotPassword, ConfirmForgotPassword, ChangePassword, GetUser, UpdateUserAttributes, DeleteUser, CreateGroup, DeleteGroup, GetGroup, ListGroups, ListUsersInGroup, CreateUserPoolDomain, DeleteUserPoolDomain, DescribeUserPoolDomain, GetUserPoolMfaConfig, SetUserPoolMfaConfig, AssociateSoftwareToken, VerifySoftwareToken, TagResource, UntagResource, ListTagsForResource; Identity Pools: CreateIdentityPool, DeleteIdentityPool, DescribeIdentityPool, ListIdentityPools, UpdateIdentityPool, GetId, GetCredentialsForIdentity, GetOpenIdToken, SetIdentityPoolRoles, GetIdentityPoolRoles, ListIdentities, DescribeIdentity, MergeDeveloperIdentities, UnlinkDeveloperIdentity, UnlinkIdentity, TagResource, UntagResource, ListTagsForResource; OAuth2: /oauth2/token (client_credentials)	Stub JWT tokens (structurally valid base64url JWTs); SRP auth returns PASSWORD_VERIFIER challenge; confirmation codes hardcoded (signup: 123456, forgot-password: 654321); MFA config stored in-memory

---

Real Database Endpoints (RDS)

When you create an RDS instance, MiniStack starts a real database container and returns the actual connection endpoint:

import boto3
import psycopg2  # pip install psycopg2-binary

rds = boto3.client("rds", endpoint_url="http://localhost:4566",
                   aws_access_key_id="test", aws_secret_access_key="test", region_name="us-east-1")

resp = rds.create_db_instance(
    DBInstanceIdentifier="mydb",
    DBInstanceClass="db.t3.micro",
    Engine="postgres",
    MasterUsername="admin",
    MasterUserPassword="password",
    DBName="appdb",
    AllocatedStorage=20,
)

endpoint = resp["DBInstance"]["Endpoint"]
# Connect directly — it's a real Postgres instance
conn = psycopg2.connect(
    host=endpoint["Address"],   # localhost
    port=endpoint["Port"],      # 15432 (auto-assigned)
    user="admin",
    password="password",
    dbname="appdb",
)

Supported engines: postgres, mysql, mariadb, aurora-postgresql, aurora-mysql

---

Real Redis Endpoints (ElastiCache)

import boto3
import redis  # pip install redis

ec = boto3.client("elasticache", endpoint_url="http://localhost:4566",
                  aws_access_key_id="test", aws_secret_access_key="test", region_name="us-east-1")

resp = ec.create_cache_cluster(
    CacheClusterId="my-redis",
    Engine="redis",
    CacheNodeType="cache.t3.micro",
    NumCacheNodes=1,
)

node = resp["CacheCluster"]["CacheNodes"][0]["Endpoint"]
r = redis.Redis(host=node["Address"], port=node["Port"])
r.set("key", "value")
print(r.get("key"))  # b'value'

A Redis sidecar is also always available at localhost:6379 when using Docker Compose.

---

Athena with Real SQL

Athena queries run via DuckDB and can query files in your local S3 data directory:

import boto3, time

athena = boto3.client("athena", endpoint_url="http://localhost:4566",
                      aws_access_key_id="test", aws_secret_access_key="test", region_name="us-east-1")

# Query runs real SQL via DuckDB
resp = athena.start_query_execution(
    QueryString="SELECT 42 AS answer, 'hello' AS greeting",
    ResultConfiguration={"OutputLocation": "s3://athena-results/"},
)
query_id = resp["QueryExecutionId"]

# Poll for result
while True:
    status = athena.get_query_execution(QueryExecutionId=query_id)
    if status["QueryExecution"]["Status"]["State"] == "SUCCEEDED":
        break
    time.sleep(0.1)

results = athena.get_query_results(QueryExecutionId=query_id)
for row in results["ResultSet"]["Rows"][1:]:  # skip header
    print([col["VarCharValue"] for col in row["Data"]])
# ['42', 'hello']

---

ECS with Real Containers

import boto3

ecs = boto3.client("ecs", endpoint_url="http://localhost:4566",
                   aws_access_key_id="test", aws_secret_access_key="test", region_name="us-east-1")

ecs.create_cluster(clusterName="dev")

ecs.register_task_definition(
    family="web",
    containerDefinitions=[{
        "name": "nginx",
        "image": "nginx:alpine",
        "cpu": 128,
        "memory": 256,
        "portMappings": [{"containerPort": 80, "hostPort": 8080}],
    }],
)

# This actually runs an nginx container via Docker
resp = ecs.run_task(cluster="dev", taskDefinition="web", count=1)
task_arn = resp["tasks"][0]["taskArn"]

# Stop it (removes the container)
ecs.stop_task(cluster="dev", task=task_arn)

---

Configuration

Variable	Default	Description
GATEWAY_PORT	4566	Port to listen on
MINISTACK_HOST	localhost	Hostname used in SQS queue URLs returned to clients
LOG_LEVEL	INFO	DEBUG, INFO, WARNING, ERROR
S3_PERSIST	0	Set 1 to persist S3 objects to disk
S3_DATA_DIR	/tmp/localstack-data/s3	S3 persistence directory
REDIS_HOST	redis	Redis host for ElastiCache fallback
REDIS_PORT	6379	Redis port for ElastiCache fallback
RDS_BASE_PORT	15432	Starting host port for RDS containers
ELASTICACHE_BASE_PORT	16379	Starting host port for ElastiCache containers
PERSIST_STATE	0	Set 1 to persist service state across restarts
STATE_DIR	/tmp/ministack-state	Directory for persisted state files

State Persistence

When PERSIST_STATE=1, MiniStack saves service state to STATE_DIR on shutdown and reloads it on startup. Writes are atomic (write-to-tmp then rename) to prevent corruption on crash.

Services currently supporting persistence: API Gateway v1, API Gateway v2

docker run -p 4566:4566 \
  -e PERSIST_STATE=1 \
  -e STATE_DIR=/data/ministack-state \
  -v /tmp/ministack-data:/data \
  nahuelnucera/ministack

Lambda Warm Starts

MiniStack keeps Python Lambda functions warm between invocations. After the first call (cold start), the handler module stays imported in a persistent subprocess. Subsequent calls skip the import step, matching real AWS warm-start behaviour and making test suites significantly faster.

---

Architecture

                    ┌─────────────────────────────────────────┐
 AWS CLI / boto3    │         ASGI Gateway  :4566             │
 Terraform / CDK ──►│  ┌───────────────────────────────────┐  │
 Any AWS SDK        │  │          Request Router            │  │
                    │  │  1. X-Amz-Target header            │  │
                    │  │  2. Authorization credential scope  │  │
                    │  │  3. Action query param              │  │
                    │  │  4. URL path pattern                │  │
                    │  │  5. Host header                     │  │
                    │  │  6. Default → S3                    │  │
                    │  └──────────────┬────────────────────┘  │
                    │                 │                        │
                    │  ┌──────────────▼──────────────────┐    │
                    │  │         Service Handlers         │    │
                    │  │                                  │    │
                    │  │  S3    SQS    SNS    DynamoDB     │    │
                    │  │  Lambda   IAM   STS   Secrets    │    │
                    │  │  SSM   EventBridge   Kinesis     │    │
                    │  │  CW Logs  CW Metrics  SES        │    │
                    │  │  Step Functions  API GW v1/v2    │    │
                    │  │  ECS   RDS   ElastiCache  Glue   │    │
                    │  │  Athena  Firehose  Route53        │    │
                    │  │  Cognito  EC2                    │    │
                    │  └──────────────────────────────────┘    │
                    │                                          │
                    │  In-Memory Storage + Optional Docker     │
                    └─────────────────────────────────────────┘
                                        │
                         ┌──────────────┼──────────────┐
                         ▼              ▼              ▼
                    Redis:6379    Postgres:15432+  MySQL:15433+
                    (ElastiCache)    (RDS)           (RDS)

---

Running Tests

# Install test dependencies
pip install boto3 pytest duckdb docker cbor2

# Start MiniStack
docker compose up -d

# Run the full test suite (644 tests across all 26 services)
pytest tests/ -v

Expected output:

collected 644 items

tests/test_services.py::test_s3_create_bucket PASSED
...
tests/test_services.py::test_app_asgi_callable PASSED

644 passed in ~60s

---

Terraform / CDK / Pulumi

Terraform

provider "aws" {
  region                      = "us-east-1"
  access_key                  = "test"
  secret_key                  = "test"
  skip_credentials_validation = true
  skip_metadata_api_check     = true
  skip_requesting_account_id  = true

  endpoints {
    s3             = "http://localhost:4566"
    sqs            = "http://localhost:4566"
    dynamodb       = "http://localhost:4566"
    lambda         = "http://localhost:4566"
    iam            = "http://localhost:4566"
    sts            = "http://localhost:4566"
    secretsmanager = "http://localhost:4566"
    ssm            = "http://localhost:4566"
    kinesis        = "http://localhost:4566"
    sns            = "http://localhost:4566"
    rds            = "http://localhost:4566"
    ecs            = "http://localhost:4566"
    glue           = "http://localhost:4566"
    athena         = "http://localhost:4566"
    elasticache    = "http://localhost:4566"
    stepfunctions  = "http://localhost:4566"
    cloudwatch     = "http://localhost:4566"
    logs           = "http://localhost:4566"
    events         = "http://localhost:4566"
    ses            = "http://localhost:4566"
    apigateway     = "http://localhost:4566"
    firehose       = "http://localhost:4566"
    route53        = "http://localhost:4566"
    cognitoidp     = "http://localhost:4566"
    cognitoidentity = "http://localhost:4566"
    ec2             = "http://localhost:4566"
  }
}

AWS CDK

// cdk.json or in your app
const app = new cdk.App();
// Set endpoint override via environment
process.env.AWS_ENDPOINT_URL = "http://localhost:4566";

Pulumi

# Pulumi.dev.yaml
config:
  aws:endpoints:
    - s3: http://localhost:4566
      dynamodb: http://localhost:4566
      # ... etc

---

Comparison

Feature	MiniStack	LocalStack Free	LocalStack Pro
S3, SQS, SNS, DynamoDB	✅	✅	✅
Lambda (Python execution)	✅	✅	✅
IAM, STS, SecretsManager	✅	✅	✅
CloudWatch Logs	✅	✅	✅
SSM Parameter Store	✅	✅	✅
EventBridge	✅	✅	✅
Kinesis	✅	✅	✅
SES	✅	✅	✅
Step Functions	✅	✅	✅
RDS (real DB containers)	✅	❌	✅
ElastiCache (real Redis)	✅	❌	✅
ECS (real Docker containers)	✅	❌	✅
Athena (real SQL via DuckDB)	✅	❌	✅
Glue Data Catalog + Jobs	✅	❌	✅
API Gateway v2 (HTTP API)	✅	✅	✅
API Gateway v1 (REST API)	✅	✅	✅
Firehose	✅	✅	✅
Route53	✅	✅	✅
Cognito	✅	✅	✅
EC2	✅	✅	✅
CloudFormation	❌	partial	✅
Cost	Free	Was free, now paid	$35+/mo
Docker image size	~150MB	~1GB	~1GB
Memory at idle	~30MB	~500MB	~500MB
Startup time	~2s	~15-30s	~15-30s
License	MIT	BSL (restricted)	Proprietary

---

Contributing

PRs welcome. The codebase is intentionally simple — each service is a single self-contained Python file in ministack/services/. Adding a new service means:

1. Create ministack/services/myservice.py with an async def handle_request(...) function and a reset() function
2. Add it to SERVICE_HANDLERS in ministack/app.py
3. Add detection patterns to ministack/core/router.py
4. Add a fixture to tests/conftest.py and tests to tests/test_services.py

See CONTRIBUTING.md for a full walkthrough.

---

License

MIT — free to use, modify, and distribute. No restrictions.

Copyright (c) 2024 MiniStack Contributors

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.