Floci Claims a 24 ms Start and MIT Licence as the Free LocalStack, and Its Issue Tracker Lists the Gaps

Floci, an MIT-licensed local AWS emulator under the floci-io GitHub organisation, shows 29.7k stars and 3.3k forks on its repository page as of Nov. 5. The project positions itself as the free replacement for LocalStack Community, which stopped being free of an account in March 2026.

Stars are interest, not adoption, and the repository does not say how many teams run it in CI. What it does publish is a comparison table, and every figure in it is the project's own.

What LocalStack changed in March

LocalStack said in a post by CTO and co-CEO Waldemar Hummer and COO and co-CEO Gerta Sheganaku, first published Dec. 18, 2025 and updated March 17, 2026, that the Community and Pro editions would merge into a single image at localstack/localstack on Docker Hub. That image requires an auth token, and an update note says the free tier is for non-commercial use only.

LocalStack's advice for anyone who does not want a token is to pin a fixed version, with 4.12 as its example. Pinned tags keep running without authentication, but the post says they get no further updates, security patches or backports.

That is the opening Floci walks through. The task it solves is plain: a team whose CI pulled localstack/localstack:latest now has to either create a token, pay, or freeze on an unpatched tag.

The numbers Floci publishes about itself

The repository's table compares Floci with LocalStack Community. The page does not say what machine produced the figures or how many runs were taken, so treat them as vendor-supplied.

Measure	Floci	LocalStack Community
Startup	~24 ms	~3.3 s
Idle memory	~13 MiB	~143 MiB
Docker image	~90 MB	~1.0 GB

1. Floci13 MiB
2. LocalStack Community143 MiB

Source: github.com/floci-io/floci README comparison table (vendor-supplied), accessed 2026-11-05

The page also claims "2,576 automated compatibility tests across 5 SDKs and 3 IaC tools". It lists a roughly 40 MB native binary, serves on port 4566, and needs no account or token. Stable releases ship on the 15th and the last day of each month.

Some services run in-process while others, such as Lambda, RDS and EKS, use real Docker containers. So the 13 MiB idle figure describes an emulator with nothing launched, not a stack with a database in it.

What the open issues say

The tracker showed 130 open issues on Nov. 5, and the newest page is a useful map of where an emulator and AWS still disagree. None is labelled as a security issue.

• Issue 7551 and a duplicate, 7550, report that CloudFormation SetStackPolicy and GetStackPolicy are stubs that store and return nothing.
• Issue 7521 reports that SQS requests with a trailing slash or a /queue/{region}/ prefix are routed to S3.
• Issue 7356 reports that an EventBridge wildcard event pattern matches nothing.
• Issue 7345 reports that the CloudFormation custom resource ResponseURL uses http under TLS, which breaks Node https handlers.

A test suite that passes against an emulator can still fail in a real account, because a stub that returns success hides the miss. That risk is not unique to Floci, but the 2,576-test figure does not size it.

Star totals deserve the same caution here as for claude-mem at 112,014 stars. And a Zig libc rewrite that made SQLite about 12,000x slower on a 1.2 MB input is a reminder that a speed figure belongs to the input it was measured on.

The next release is due on the last day of November, going by the project's stated schedule. Whether issues 7550 and 7551 are closed by then is a cleaner test of the project than its startup time.