fakecloud FAQ
Frequently asked questions about fakecloud: the free, open-source local AWS cloud emulator. Installation, LocalStack migration, supported services, licensing, and more.
Common questions about fakecloud. For setup guides and tutorials, see the docs and blog.
What is fakecloud?
fakecloud is a free, open-source local AWS cloud emulator for integration testing and local development. It runs on a single port (4566), requires no account or auth token, and aims for 100% behavioral conformance with real AWS on every service it implements. AGPL-3.0 licensed.
Is fakecloud free?
Yes. AGPL-3.0, free for commercial use. Using fakecloud as a dev/test dependency has zero AGPL implications for your application — the copyleft clause only kicks in if you modify fakecloud itself and redistribute it as a network service.
Is fakecloud a LocalStack alternative?
Yes. LocalStack replaced its open-source Community Edition with a proprietary image in March 2026 that requires an account and auth token. fakecloud is a free, open-source replacement. See the LocalStack alternative page and the migration guide.
How many AWS services does fakecloud support?
23 services and 1,680 API operations at 100% conformance per implemented service today, with more on the roadmap. The explicit goal is 100% of AWS services, each at 100% behavioral conformance, with 100% of cross-service integrations. Services land depth-first — a service is added when it passes the full Smithy-model test variants and cross-service wire-ups.
Which AWS services are supported?
S3, SQS, SNS, DynamoDB, Lambda, IAM, STS, KMS, Secrets Manager, SSM, CloudWatch Logs, CloudFormation, EventBridge, EventBridge Scheduler, SES (v2 + v1 inbound), Cognito User Pools, Kinesis, RDS, ElastiCache, Step Functions, API Gateway v2, Bedrock, Bedrock Runtime.
Does fakecloud execute Lambda code for real?
Yes. fakecloud pulls real AWS Lambda runtime containers and executes your handler against them. All 13 official runtimes: Node.js 18/20/22, Python 3.9-3.12, Java 11/17/21, .NET 6/8, Ruby 3.2, Go, custom provided.al2 and provided.al2023. See Test Lambda locally.
Does fakecloud run real databases for RDS?
Yes. RDS emulation pulls real PostgreSQL / MySQL / MariaDB Docker images and runs them as the DB instance. Your SQL schema, indexes, triggers, and extensions work because the engine is real. See Local RDS for tests.
Does fakecloud run real Redis for ElastiCache?
Yes. ElastiCache runs real Redis / Valkey Docker images. LPUSH, ZADD, XADD, streams, pub/sub, Lua scripts — all work. See Local ElastiCache for tests.
Do S3 notifications fire Lambda?
Yes, end-to-end. When an object is created in S3, any Lambda subscribed via bucket notification configuration fires for real — the Lambda code runs in a real runtime container. Same for SNS / SQS subscriptions.
How do I install fakecloud?
One-line install script:
curl -fsSL https://raw.githubusercontent.com/faiscadev/fakecloud/main/install.sh | bash
fakecloudOr Docker: docker run --rm -p 4566:4566 ghcr.io/faiscadev/fakecloud. Or cargo install fakecloud.
Does fakecloud work with Terraform?
Yes. CI runs the upstream hashicorp/terraform-provider-aws TestAcc* suites against fakecloud on every commit. See Terraform local development for AWS.
Does fakecloud work with CDK?
Yes. Use the plain cdk binary with AWS_ENDPOINT_URL=http://localhost:4566, or cdklocal. See CDK local testing.
Can I use fakecloud in CI?
Yes. Fits as a GitHub Actions service container, GitLab CI service, CircleCI service, or install-and-run background step. ~500ms startup means negligible CI overhead. See Integration testing AWS in CI.
Does fakecloud require Docker?
To run fakecloud itself, no. Single binary, ~19 MB. Docker is required for services that run real containers (Lambda runtimes, RDS engines, ElastiCache engines) — same as LocalStack Pro requires.
Is fakecloud written from scratch?
Yes. Written in Rust, no LocalStack code was used. LocalStack is written in Python; fakecloud is written in Rust and ships as a single static binary.
How does fakecloud validate correctness?
Every commit runs 54,000+ conformance test variants generated from AWS's own Smithy models, plus end-to-end tests using the official AWS SDKs, plus the upstream hashicorp/terraform-provider-aws TestAcc* suites. If fakecloud behaves differently from real AWS, that's a bug — open an issue.
Can AI coding agents (Claude Code, Cursor, Copilot) use fakecloud?
Yes. Paste-ready snippets for CLAUDE.md, .cursor/rules, and .github/copilot-instructions.md are in the README and this blog post. Agents can also fetch https://fakecloud.dev/llms.txt for structured API surface.
Is fakecloud production-ready cloud infrastructure?
No. fakecloud is a testing and local-development tool. It is not production AWS and is not intended to be. For production, use real AWS.
How does fakecloud compare to Moto?
Moto is a Python library that patches boto3 inside a test process. fakecloud is a real HTTP server on port 4566. Moto is fast and Python-only; fakecloud is language-agnostic and runs real Lambda / RDS / Redis. See fakecloud vs Moto.
How does fakecloud compare to MinIO?
MinIO is production-grade S3-compatible storage. fakecloud is an AWS testing emulator that happens to do S3 among 22 other services. Different tools for different jobs. See fakecloud vs MinIO.
How does fakecloud compare to DynamoDB Local?
DynamoDB Local is AWS's official DynamoDB emulator (DynamoDB only). fakecloud emulates DynamoDB plus 22 other AWS services, with Streams fired through real Lambda execution. See fakecloud vs DynamoDB Local.
Where can I ask questions or report bugs?
GitHub issues: github.com/faiscadev/fakecloud/issues. The roadmap is demand-driven — service requests help prioritize what gets built next.