Floci is a suite of local cloud emulators that let you run AWS, Azure, and GCP services on your own machine, with no accounts, auth tokens, or usage limits. Every emulator is built with Quarkus, compiled to a native binary with GraalVM Mandrel, starts in ~24 ms, and idles around 13 MiB. Everything is MIT-licensed and free forever.
The name comes from cirrocumulus floccus, a small, fluffy cloud formation. That’s the design goal: minimal, lightweight, and always free.
Website: floci.io · GitHub: github.com/floci-io
The Floci family
- Floci (AWS): a drop-in replacement for LocalStack,
emulating 47 services on port
4566. - Floci-Az (Azure): 8 services on port
4577, including Blob, Queue, and Table Storage, Functions, Key Vault, Event Hubs, and Service Bus. - Floci-GCP (GCP): 7 services on port
4588, including Cloud Storage, Pub/Sub, Firestore, Datastore, Secret Manager, IAM, and Managed Kafka.
Native Floci (AWS) vs LocalStack
| Metric | Native Floci | LocalStack | Advantage |
|---|---|---|---|
| Startup Time | ~24 ms | ~3,300 ms | 138× faster |
| Idle Memory | ~13 MiB | ~143 MiB | 91% less |
| Lambda Latency | 2 ms avg | 10 ms avg | 5× faster |
| Lambda Throughput | 289 req/s | 120 req/s | 2.4× faster |
| Docker Image Size | ~90 MB | ~1.0 GB | 11× smaller |
| Price | Free Forever | Auth Token Req. | $0 / No Auth |
Supported AWS Services
SSM · SQS · SNS · S3 · DynamoDB · DynamoDB Streams · Lambda · API Gateway REST · API Gateway v2 · IAM · STS · Cognito · KMS · Kinesis · Secrets Manager · CloudFormation · Step Functions · ElastiCache · RDS · MSK · EventBridge · EventBridge Scheduler · CloudWatch Logs · CloudWatch Metrics · ECS · EC2 · ACM · ECR · SES · SES v2 · OpenSearch · Athena · Glue · Data Firehose · AppConfig · AppConfigData · Bedrock Runtime · EKS
Lambda functions run inside real Docker containers (Node.js, Python, Java, Go, Ruby) with a warm pool for sub-millisecond reuse. ElastiCache, RDS, MSK, ECS, EKS, ECR, and OpenSearch spin up real Docker containers on demand. All 47 services are free, with no auth tokens required.
Stack
- Java 25 + Quarkus 3.x: reactive, lightweight runtime
- GraalVM Mandrel: compiles to a native binary with no JVM required
- Vert.x: embedded HTTP server for the Lambda Runtime API
- docker-java: container lifecycle management
- MIT License
Quick Start
# AWS (port 4566)
docker run --rm -p 4566:4566 floci/floci:latest
# Azure (port 4577)
docker run --rm -p 4577:4577 floci/floci-az:latest
# GCP (port 4588)
docker run --rm -p 4588:4588 floci/floci-gcp:latest
Then point any AWS, Azure, or GCP SDK or CLI at the matching local endpoint with any dummy credentials.
Read the full deep-dive on the blog.