floci-io/floci

Floci is worth a look if you write AWS-dependent code and want it running locally without an account, auth token or paid tier. The catch: it emulates a broad surface, so you need to test the specific services you rely on rather than assume parity.

The problem

A developer wants to exercise S3, DynamoDB or a Lambda handler before pushing. Today that means either a shared cloud account, credentials, and cleanup, or a narrow mock that drifts from real AWS behavior. Floci replaces that step with a local endpoint: the same SDK and CLI calls go to http://localhost:4566, and resources appear locally. The result is a local workflow that does not touch a cloud account for day-to-day development.

What's different

Floci's bet is breadth combined with real Docker for services where behavior matters. Lambda, RDS, ECS, EC2, EKS and several others run as Docker-backed workloads rather than shallow HTTP mocks, according to the README. Stateless services are handled directly by the emulator, and storage can be in-memory, persistent, hybrid or write-ahead-log, so you choose how much state survives a restart. The project also ships a compatibility suite with 2,576 automated tests across five SDKs and Terraform, OpenTofu and CDK, which is the most useful evidence that standard tooling works against it.

The trade-off is that a broad service list is not a guarantee of behavioral fidelity for every API. The compatibility tests are self-reported by the project, and the README's comparison table is the author's own claims, including startup and memory figures. If you depend on subtle AWS semantics, per-service differences may still surface.

Who should try it

Good fit: a developer who runs AWS SDK code or Terraform locally and wants a free endpoint with no login friction; a team wiring CI that needs AWS-shaped services on each run; someone migrating off a community edition that now requires tokens. Poor fit: a team that needs exact production parity for a service not represented in the compatibility suite, or one already comfortable with a different emulator and no migration pressure. The CLI quick start is optional; the README also documents Docker Compose and points to a Terraform guide.

Requirements and limitations

Docker is central: the README says the CLI is the fastest path, and Docker-backed services and the web console rely on it. The console at /_floci/ui runs as a sidecar container that is pulled on first request, so the first open needs network access and Docker networking. Persistent and WAL storage modes require decisions about where state lives; switching modes has ongoing implications for test isolation. Broad compatibility is tested, but the README's service table is large enough that you should check the compatibility tests for your specific SDK and tooling before committing. There is also a published console contract if the built-in UI does not suit you.

HotRepo's take

HotRepo's dated view is thin: 27,096 stars on 2026-10-24 and 27,097 on 2026-10-25, with two daily-board appearances in that window. That is a snapshot, not evidence of durable momentum, so persistence cannot be judged yet. The project was created on 2026-02-18. For adoption, verify the compatibility coverage for the exact services and IaC workflow you use, not just the headline test count.