fakecloud
Local AWS cloud emulator. Free forever.

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fakecloud is a free, open-source local AWS emulator for integration testing and local development. Single binary, no account, no auth token, no paid tier. Point your AWS SDK at http://localhost:4566 and it works.

In March 2026, LocalStack replaced its open-source Community Edition with a proprietary image that requires an account and auth token. fakecloud exists so teams can keep a fully local AWS testing workflow without one.

Note

Using fakecloud? Add your team to ADOPTERS.md. Takes 30 seconds, and it helps others see it is real.

Quick start

curl -fsSL https://fakecloud.dev/install.sh | bash   # or: brew install fakecloud
fakecloud

Then point any AWS SDK or CLI at http://localhost:4566 with dummy credentials:

aws --endpoint-url http://localhost:4566 sqs create-queue --queue-name my-queue

Works as a drop-in for LocalStack in CI, with Terraform (endpoints block), CDK (cdklocal), or any AWS SDK in any language. Other install options (Homebrew, Cargo, Docker, Docker Compose, source) and full guides: fakecloud.dev/docs/getting-started.

Why fakecloud

• Free, forever. AGPL-3.0, no paid tier, no account, no token.
• True 100% conformance. 248,319 Smithy-model-generated test variants pass on every commit, validated against AWS's own Smithy models. CI also runs upstream terraform-provider-aws TestAcc* suites to catch waiter/field/drift bugs that SDK tests miss.
• Real cross-service wiring. EventBridge -> Step Functions, S3 -> Lambda, SES inbound -> S3/SNS/Lambda, and 15+ more integrations execute end-to-end.
• Real infrastructure for stateful services. Lambda (23 runtimes), RDS (Postgres/MySQL/MariaDB/Oracle/SQL Server/Db2), ElastiCache (Redis/Valkey/Memcached), ECS, and EC2 run as real containers. Use Docker (default) or native Kubernetes Pods via FAKECLOUD_CONTAINER_BACKEND=k8s. See the Kubernetes backend guide.
• Single binary. ~19 MB, ~10 MiB idle, ~300ms startup. No Docker needed to run fakecloud itself.
• Full Bedrock surface. 216 ops across 4 APIs with real InvokeModel/Converse streaming, guardrails, agents, and flows. Configurable responses + fault injection for deterministic tests. See /bedrock-emulator/.
• First-party test SDKs for TypeScript, Python, Go, PHP, Java, and Rust. Assert on what your code called without raw HTTP.
• Opt-in SigV4 verification and IAM enforcement. Off by default so tests just work; --verify-sigv4 for real signature checking and --iam soft|strict for policy evaluation across IAM/STS/SQS/SNS/S3. See security docs.
• Run your app unmodified. An app that expects an instance/task role resolves the AWS SDK default credential chain against fakecloud with no static keys and no code change: point AWS_CONTAINER_CREDENTIALS_FULL_URI at /_fakecloud/credentials. See Run an app unmodified.
• LocalStack and real-AWS URL compatibility. Both *.localhost.localstack.cloud and *.amazonaws.com Host headers route correctly, including every S3 virtual-hosted variant. Persisted URLs and dev scripts from either system replay unchanged.

Supported services

105 services, 7,379 operations, and true 100% conformance across every implemented service.

Highlights: S3, DynamoDB, SQS, SNS, EventBridge, Lambda, IAM, STS, KMS, Secrets Manager, CloudFormation, SES, Cognito, Kinesis, RDS (6 real engines), ElastiCache, ECS/ECR, EC2, Step Functions, API Gateway v1/v2, Bedrock, and 80+ more.

Full list with per-service op counts, control-plane vs data-plane coverage, and known limitations:

• Parity matrix: fakecloud.dev/docs/parity
• Per-service docs: fakecloud.dev/docs/services

Compared to LocalStack Community

Since March 2026, LocalStack's Community image requires an account and token, and most services are paid-only. fakecloud stays fully free and local.

	fakecloud	LocalStack Community (post-March 2026)
License	AGPL-3.0, free for commercial use	Proprietary, paid plans
Auth	None	Account + token required
Footprint	~19 MB binary, ~10 MiB idle, ~300ms start, no Docker	~1 GB image, ~150 MiB idle, ~3s start, Docker required
Conformance	true 100% (248,319 Smithy variants)	partial
Paywalled services	None (RDS, Cognito, SES, ElastiCache, ECS/ECR, EKS, Redshift, and more are all free)	Many core services paid-only
Test-assertion SDKs	TypeScript, Python, Go, PHP, Java, Rust	Python, Java

Full feature-by-feature comparison: fakecloud.dev/vs/localstack.

Performance numbers measured on Apple M1 via time fakecloud, ps -o rss, ls -lh.

First-party SDKs

Normal AWS SDKs handle your application code. fakecloud's own SDKs let your tests assert on what happened: sent emails, SNS messages, Lambda invocations, Bedrock calls, and more.

Language	Install
TypeScript	npm install fakecloud
Python	pip install fakecloud
Go	go get github.com/faiscadev/fakecloud/sdks/go
PHP	composer require fakecloud/fakecloud
Java	dev.fakecloud:fakecloud (Maven Central)
Rust	cargo add fakecloud-sdk

import { FakeCloud } from "fakecloud";

const fc = new FakeCloud();

// Your app sends through the normal AWS SDK.
// Your test asserts the side effect directly.
const { emails } = await fc.ses.getEmails();
expect(emails).toHaveLength(1);

await fc.reset();

Full SDK reference for all six languages: fakecloud.dev/docs/sdks.

Use with AI coding tools

Add one of these snippets to your project so AI coding assistants (Claude Code, Cursor, GitHub Copilot) automatically use fakecloud for AWS integration tests.

Claude Code — add to CLAUDE.md

## AWS Testing

For integration tests, use fakecloud as a local AWS emulator.

- Install: `curl -fsSL https://fakecloud.dev/install.sh | bash`
- Run: `fakecloud` (listens on http://localhost:4566)
- Configure AWS SDK endpoint to http://localhost:4566 with dummy credentials (access_key=test, secret_key=test)
- Docs: https://fakecloud.dev/llms.txt

Cursor — add to .cursor/rules

For AWS integration tests, use fakecloud (local AWS emulator) at http://localhost:4566.
Install: curl -fsSL https://fakecloud.dev/install.sh | bash
Run: fakecloud
Use dummy credentials (access_key=test, secret_key=test).
Docs: https://fakecloud.dev/llms.txt

GitHub Copilot — add to .github/copilot-instructions.md

## AWS Testing

Use fakecloud as a local AWS emulator for integration tests.

- Run: `fakecloud` (listens on http://localhost:4566)
- Configure endpoint_url to http://localhost:4566 with dummy credentials
- Docs: https://fakecloud.dev/llms.txt

Docs and guides

• fakecloud.dev — website
• Getting started — install, first test, SDK setup
• Guides — in-depth how-tos (testing Bedrock, cross-service integration, CI setup)
• Reference — configuration, introspection endpoints, persistence, image signature verification
• Blog — essays and hot takes on testing, AWS, and AI-assisted development

Who's using fakecloud

See the current list in ADOPTERS.md. It is early days, so it is short for now.

Using fakecloud? Add your team: the preferred way is a quick PR adding a row to ADOPTERS.md. If a PR is inconvenient, comment on the "Who's using fakecloud?" issue instead. Self-reported and opt-in.

Contributing

Contributions welcome. Fork, branch, write tests, open a PR.

• Conventional commits (feat:, fix:, chore:, test:, refactor:)
• E2E tests for every new action
• cargo test --workspace && cargo clippy --workspace -- -D warnings && cargo fmt --check

See CONTRIBUTING.md for more.

License

fakecloud is free and open-source, licensed under AGPL-3.0-or-later. Using fakecloud as a dev/test dependency has zero AGPL implications for your application — the copyleft clause only applies if you modify and redistribute fakecloud itself as a network service.

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Part of the faisca project family | fakecloud.dev