I built a free LocalStack alternative in Go — v0.6.0 is out with 37 AWS services

#aws #go #opensource #showdev

So I've been working on this project called CloudDev for a while now. It's basically a local AWS emulator — think LocalStack but free, open source, and a single Go binary with zero dependencies.

I just shipped v0.6.0 and wanted to share what's new.

Why I built this

Honestly? LocalStack's free tier kept getting more and more limited. Every time I needed a service it was "pro only". I just wanted to test my AWS code locally without spinning up real infrastructure or paying for a subscription.

So I started building CloudDev. The goal was simple — emulate the AWS services I actually use, make it work with the existing AWS CLI and SDKs without any config changes, and keep it as a single binary I can just run anywhere.

What's new in v0.6.0

This release was focused on infrastructure completeness. I added 8 new services:

Kinesis Data Streams — shards, records, iterators, the whole thing
Kinesis Firehose — delivery streams, PutRecord, PutRecordBatch
ECS — clusters, task definitions, run/stop tasks
ECR — repositories, image push/pull, auth token
CloudFront — distributions, origins, invalidations
AppSync — GraphQL APIs, data sources, schema upload
Athena — query execution, results, named queries
ACM — certificates, tags, mock PEM output

That brings the total to 37 AWS services across 47 modules.

Quick start

git clone https://github.com/Jeffrin-dev/CloudDev.git
cd CloudDev
go build -o clouddev .

./clouddev init my-app
cd my-app
../clouddev up

That's it. All 37 services start up immediately.

Some examples

# Kinesis
aws --endpoint-url=http://localhost:4568 kinesis create-stream \
  --stream-name my-stream --shard-count 2

aws --endpoint-url=http://localhost:4568 kinesis put-record \
  --stream-name my-stream --data "hello" --partition-key "pk1"

# ECS
aws --endpoint-url=http://localhost:4561 ecs create-cluster \
  --cluster-name my-cluster

aws --endpoint-url=http://localhost:4561 ecs register-task-definition \
  --family my-task \
  --container-definitions '[{"name":"app","image":"nginx","memory":128}]'

# ECR
aws --endpoint-url=http://localhost:4562 ecr create-repository \
  --repository-name my-repo

aws --endpoint-url=http://localhost:4562 ecr get-authorization-token

# Athena
aws --endpoint-url=http://localhost:4564 athena start-query-execution \
  --query-string "SELECT * FROM my_table" \
  --query-execution-context Database=mydb

# ACM
aws --endpoint-url=http://localhost:4560 acm request-certificate \
  --domain-name example.com

No endpoint configuration files, no fake credentials setup beyond the usual AWS_ACCESS_KEY_ID=test — just point the CLI at localhost and it works.

Full service list

Service	Port
ACM	4560
ECS	4561
ECR	4562
CloudFront	4563
Athena	4564
S3	4566
AppSync	4567
Kinesis Data Streams	4568
DynamoDB	4569
DynamoDB Streams	4570
Kinesis Firehose	4571
API Gateway	4572
API Gateway v2	4573
Lambda	4574
SNS	4575
SQS	4576
Lambda Layers	4578
SES	4579
Dashboard	4580
CloudFormation	4581
CloudWatch Metrics	4582
SSM Parameter Store	4583
Secrets Manager	4584
Step Functions	4585
CloudWatch Logs	4586
EventBridge	4587
X-Ray	4588
Route53	4589
CloudWatch Events	4590
Bedrock	4591
STS	4592
IAM	4593
Rekognition	4594
Lambda Function URLs	4595
Cognito	4596
ElastiCache	4597/4598
KMS	4599

Web dashboard

There's also a web dashboard at localhost:4580 that shows all running services in real time. It flips red when the server goes down which is a small thing but honestly pretty useful when you're running tests.

How it's built

It's pure Go 1.22, no external runtime dependencies. Each AWS service is its own HTTP server listening on its port, routing requests by the X-Amz-Target header or REST path depending on the service protocol.

One thing I learned the hard way — AWS CLI doesn't always use the protocol the docs say it does. KMS, Kinesis, ECS, ECR all use JSON + X-Amz-Target. CloudFront uses REST + XML. AppSync uses REST + JSON. I had to sniff actual requests with nc a few times to figure out what the CLI was actually sending.