fakecloud vs floci
How fakecloud compares to floci. Both free, open-source AWS emulators positioned as LocalStack replacements.
floci is a free, open-source AWS emulator that appeared after LocalStack replaced its Community Edition with a proprietary image in March 2026. fakecloud is another option in the same space.
This page is honest positioning. I maintain fakecloud. What follows is architectural — what each project is — rather than side-by-side benchmarks I haven't personally measured across both.
Shared fundamentals
Both are free, open-source, local AWS emulators. Real HTTP server speaking the AWS wire protocol. Any AWS SDK in any language works. Both are replacements for LocalStack Community for the services each covers.
The positioning difference
floci's approach (check their site for the current details — the project publishes performance claims like startup time, memory, and SDK-test pass rate): a free LocalStack replacement. Verify their numbers against the version you'd actually run.
fakecloud's approach: depth-first, explicit goal. 100% of AWS services, each at 100% behavioral conformance, with 100% of cross-service integrations. A service is added when it passes the full Smithy-model test variants and cross-service wire-ups, not when the API surface looks filled in. 23 services shipped today. Built around real Lambda execution (13 runtimes in Docker), real stateful backends (Postgres/MySQL/MariaDB/Redis/Valkey via Docker), real cross-service wiring, and validation on every commit against AWS's own Smithy models (59,000+ generated test variants) plus the upstream hashicorp/terraform-provider-aws TestAcc* suites.
Breadth-first and depth-first are both valid tradeoffs. Pick by whether your tests need real downstream execution and cross-service flows, or surface-level plausibility across more services.
How to pick
Run your actual test suite against both. Numbers published on landing pages are marketing; numbers your tests produce against your services are signal.
fakecloud specifics
| Feature | fakecloud |
|---|---|
| Language | Rust |
| Distribution | Single static binary (~19 MB) + Docker image |
| Startup | ~500ms |
| Idle memory | ~10 MiB |
| Services covered today | 23 (1,680 ops) at 100% conformance |
| Lambda execution | Real code in 13 Docker runtime containers |
| RDS | Real PostgreSQL/MySQL/MariaDB via Docker |
| ElastiCache | Real Redis/Valkey via Docker |
| Cross-service wiring | S3 -> Lambda, SNS fan-out, EventBridge -> Step Functions, SES inbound -> S3/SNS/Lambda, 15+ more fire end-to-end |
| Conformance methodology | Smithy-validated, 59k+ test variants per commit |
| Terraform TestAcc CI | Yes (upstream suites run against fakecloud) |
| Test-assertion SDKs | TypeScript, Python, Go, PHP, Java, Rust |
| Multi-account, SCPs, ABAC | Yes |
| License | AGPL-3.0 |
Install fakecloud
curl -fsSL https://raw.githubusercontent.com/faiscadev/fakecloud/main/install.sh | bash
fakecloud- Repo: github.com/faiscadev/fakecloud
- LocalStack alternative landing: /localstack-alternative/
- Four-way comparison: /blog/localstack-alternatives-compared/