Floci Review: Free Local AWS in 24ms, No Token, No Bill

Coding agents write cloud code faster than ever, and that speed created a problem nobody planned for. An agent that can write a Lambda function can also deploy one, and a runaway agent pointed at a real AWS account can turn a quiet afternoon into a surprise bill. The safe answer used to be LocalStack's free Community edition: run a fake AWS on your laptop and let the agent break that instead. Then, on March 23, 2026, LocalStack retired the Community edition, put its image behind an account and an auth token, and froze security updates on the old free version. Floci is the project that filled the hole. It passed 31,000 GitHub stars, topped GitHub Trending on November 3, and its pitch fits in one line: a local cloud your coding agents cannot break.

This review covers what Floci runs, what it costs, how to set it up, and where it falls short. No hands-on testing was done for this article. Every fact below comes from the project's own repository and site, LocalStack's own pages, or the reporting linked at the end, checked on November 9, 2026.

What Floci is

Floci is a free, open-source local AWS emulator for development, testing, and CI. It gives you AWS-shaped services on your own machine without a cloud account, an auth token, or paid feature gates. Point your AWS SDK, CLI, Terraform, CDK, OpenTofu, or test suite at http://localhost:4566 and keep your existing workflows. That port number is deliberate: it is the same port LocalStack used, so existing setups need an endpoint change and not much else.

The name comes from floccus, the cloud formation that looks like popcorn. Floci is the AWS member of a four-emulator family: floci-az covers Azure on port 4577 with 32 services, floci-gcp covers Google Cloud on port 4588 with 28, and floci-oci covers Oracle Cloud on port 4599 with 11. The AWS emulator carries the traction: 31,107 stars and 3,399 forks on GitHub as of November 9, 2026.

The project's homepage frames it for the agent era: "A local cloud your coding agents can't break." Agents connect with throwaway keys, so no real cloud secret reaches their context or sandbox, and the worst case is a reset local container rather than a staging environment or a bill. Our Vercel Agent-Desktop review covered the same problem from the other side, giving agents a computer they can operate. Floci gives them a cloud they can break safely.

Why it exists: LocalStack's free edition ended in March

LocalStack maintained two versions for years: a free, open-source Community edition and a paid Pro edition. In a blog post titled "The Road Ahead," LocalStack announced that beginning in March 2026 it would ship a single unified version, and running it would require an account and an auth token. The Community edition's source code stayed on GitHub, but LocalStack said it could not commit to regular updates or security patches for it.

The change went live on March 23, 2026, when LocalStack shipped version 2026.03.0, archived the Community repositories, and made the unified image refuse to start without an auth token. Floci launched the month before, in February 2026, and its own documentation describes it as the no-strings-attached alternative to the sunset Community edition. LocalStack did not go fully paid: its pricing page still offers a free Hobby plan, but the terms prohibit commercial use, and anyone running LocalStack for commercial software development is directed to Base, Ultimate, or Enterprise licenses. LocalStack also prices agentic usage separately, by sales conversation rather than a published number. The free local cloud still exists at LocalStack, but only for hobbyists, students, and open-source projects.

What it actually runs

The AWS emulator covers 128 services, according to the project's site. The list runs from the obvious, S3, SQS, SNS, DynamoDB, Lambda, IAM, KMS, Secrets Manager, Step Functions, EventBridge, API Gateway, Cognito, and CloudFormation, through databases and analytics like RDS, ElastiCache, Neptune, Redshift, Athena, and OpenSearch, and into newer territory: Bedrock, Bedrock AgentCore, and SageMaker all appear in the service table.

The important distinction is how each service runs. Floci runs real engines where fidelity matters instead of shallow mocks, in the project's own words. Lambda runs in real Docker containers with actual AWS runtimes, RDS runs on real PostgreSQL and MySQL, and ElastiCache runs on real Redis. The container-backed list also includes Neptune, MSK, ECS, EC2, EKS, OpenSearch, and CodeBuild. That is why the project can claim code an agent verifies locally behaves the same in production: the wire protocol is real, and for the heavy services, the engine is real too.

Around the services, Floci ships a browser console at http://localhost:4566/_floci/ui, four storage modes, multi-account isolation, and Testcontainers support for an isolated cloud per CI job. Terraform works through the standard HashiCorp AWS provider. Stable releases ship twice a month.

Pricing: what free actually costs

Floci costs $0. There is no paid tier, no feature flag, and no account to create. The license is MIT, which means anyone can fork the code and keep shipping it if the project ever changes direction. The same sunset that killed its predecessor cannot happen to it in the same way.

The comparison that matters is against what LocalStack charges now. Its pricing page, read on November 9, 2026, lists Base at $39 per user per month when billed annually, or $45 per user per month on a monthly commitment. Ultimate is $89 per user per month. Enterprise is custom pricing through sales. A five-person team on Base at the annual rate pays $195 a month, about £146 or C$274. Base alone is about £29 or C$55 per user per month, and Ultimate is about £66 or C$125 (1 USD = 0.7471 GBP and 1.4066 CAD on November 9, 2026, approximations).

The fine print matters more than the headline numbers. Floci's $0 covers the emulator only. The cloud services it pretends to be are free because they are fake, but the compute underneath is not: container-backed services need Docker running, and the containers they pull, real Postgres, real Redis, real Lambda runtimes, use your machine's CPU, memory, and disk. LocalStack's side has its own fine print: the free Hobby tier is non-commercial only, licenses are assigned to individual users and cannot be pooled, and the AI-agent pricing LocalStack mentions is a sales conversation rather than a published number.

Floci vs LocalStack, side by side

Floci publishes its own comparison against LocalStack Community in its README, and it is worth reading as the project's pitch rather than as an independent test. The numbers are the project's own measurements: startup in about 24 milliseconds against about 3.3 seconds, idle memory around 13 MiB against around 143 MiB, and a Docker image around 90 MB against around 1.0 GB. On the project's site, that becomes "138× faster startup and 91% less memory," which matches the arithmetic.

Two things in that table need context. First, it compares against the Community edition, frozen as of March 2026, not against LocalStack's current paid product, which has the full service catalog, Cloud Pods, Ephemeral environments, and enterprise features Floci does not try to match. Second, the table's "No" entries describe what the old Community edition lacked, not what LocalStack sells today. Floci beats the free version of LocalStack that no longer exists, on speed, memory, image size, and the absence of an account, not on breadth of features.

How to run it

Setup takes minutes, and the project documents three paths. The fastest is the official CLI: install it with the script on the project's site, then run floci start and eval $(floci env) to point your shell at the local endpoints. The second path is Docker Compose with the floci/floci:latest image on port 4566, plus the standard AWS environment variables: endpoint URL, region, and throwaway credentials. The third is a standalone native binary for Linux, macOS, and Windows. The project's README notes that each release ships the binary, but the 2.4.0 release page on GitHub lists no attached binaries as of this writing, checked via the GitHub API on November 9, so the CLI and Docker routes are the reliable ones for now.

Once it is running, the loop is ordinary AWS. Create a bucket with aws s3 mb s3://my-bucket, copy a file in, copy it back out. For CI, Floci runs as a service container in GitHub Actions: one job, one isolated cloud, teardown free.

Migrating from LocalStack is the part the project clearly spent time on. It calls itself a drop-in replacement: the port, credentials, SDK configuration, and CLI endpoint pattern work the same way, so the migration is a one-line image swap from localstack/localstack to floci/floci:latest. LocalStack environment variables are translated automatically, and init scripts mounted under /etc/localstack/init/ run unchanged. If your init scripts need the AWS CLI or boto3, use the latest-compat image variant.

The catches

Floci is nine months old, and the rough edges show in the places the project is honest about. The service table labels some services as in-process stubs, and the AI ones matter most. Bedrock Runtime returns dummy Converse and InvokeModel responses, Bedrock AgentCore returns canned agent responses, Textract returns dummy block data, and Transcribe jobs complete immediately with no real audio processing. Floci is the wrong tool for testing anything that depends on a real model response. It can test that your code calls Bedrock correctly. It cannot test what Bedrock says back.

The second catch is Docker. The lightweight services run in-process, but Lambda, RDS, ElastiCache, MSK, ECS, EC2, EKS, OpenSearch, CodeBuild, and Managed Flink all need the Docker socket. Without Docker, a third of the catalog degrades: those services fail the request that needs a container, or keep only their control plane with nothing running behind it. The project's site says so plainly, "Needs Docker or Podman running," but it is easy to miss when the headline promises a 24-millisecond start.

The third catch is youth. Floci has 62 releases and active development, with its repository last pushed on November 8, 2026, but it is a young project with no maintenance branches and releases cut from main only, twice a month. There is no long-term support release to pin to if a monthly train breaks your setup. And while "free forever" is the project's promise, promises are not guarantees. The structural guarantee is the MIT license, which lets anyone fork the code. The speed numbers deserve the same caution: they come from Floci's own comparison table, and no independent benchmark has reproduced them.

Common mistakes to avoid

• Pointing an agent at a real AWS account because the local emulator "seemed slow." The whole point is the sandbox. Set the rule in AGENTS.md first, then let the agent work.
• Reading "128 services" as "128 fully working services." Check the service table for the ones your code touches. Bedrock, Transcribe, and Textract are stubs.
• Running without Docker and wondering why Lambda does nothing. The container-backed services need the Docker socket, and the site says so on the front page.
• Pulling the old hectorvent/floci image. It no longer receives updates. The current image is floci/floci.
• Assuming the free tier of the old tool still exists. LocalStack's Hobby plan is free only for non-commercial use. Commercial work needs a paid plan or a different emulator.

Who should try it, and who should wait

Try it if you write code against AWS, if your coding agent touches cloud resources, or if you run AWS-backed tests in CI and you are tired of auth tokens and per-seat pricing. The install is a few minutes, the migration from LocalStack is an image swap, and the cost of finding out is zero. Teams already paying for LocalStack Base should still try it: a five-person team pays $2,340 a year at $39 a user per month.

Wait if you depend on LocalStack's cloud features, Cloud Pods, Ephemeral environments, or the web console's collaboration tools, or if your tests need real model responses from Bedrock rather than dummy ones. Floci is a community project with sponsors and no paid tier. That is its strength and its limit. Our AWS Infinity article covers the other side of the same trend, and Floci is the local half of that story. For a closer look at running several coding agents at once, see our Paradev review.

FAQ

Is Floci really free?

Yes. There is no paid tier, no account, and no auth token, and the MIT license lets anyone fork the code. The only costs are your own machine's CPU, memory, and disk.

Does Floci replace LocalStack?

For local development, testing, and CI, yes. It is a drop-in replacement for the retired Community edition. It does not replace LocalStack's paid cloud features like Cloud Pods or Ephemeral environments.

Do I need Docker to run Floci?

For the full service catalog, yes. The emulator itself starts without it, but the container-backed services need the Docker socket.

Can my coding agent use Floci?

Yes, and that is the project's main pitch. A skill installed with npx skills add floci-io/floci-cli teaches Claude Code, Codex, Cursor, Kiro, and other agents to run the emulators.

Is Floci safe to use for commercial work?

The MIT license permits commercial use with no payment, which is the opposite of LocalStack's free Hobby tier. That one is non-commercial only.

The bottom line

Floci exists because the free local cloud went away, and it does the job with unusual honesty about its limits. It is fast, free, and MIT-licensed, and already the tool 31,000 developers starred while LocalStack's free edition was being retired. The stubs and the Docker requirement are real, but they are documented in the project's own service table rather than hidden. If your coding agent writes cloud code, give it a cloud it cannot break: install Floci from floci.io and point your next test run at localhost.

Sources

• Floci, official GitHub repository (read November 9, 2026)
• Floci, official homepage (read November 9, 2026)
• LocalStack, official pricing page (read November 9, 2026)
• LocalStack, "The Road Ahead: Changes to LocalStack's AWS Emulators" (read November 9, 2026)
• LocalStack, "LocalStack for AWS Pricing & Packaging Updates" (February 27, 2026)
• LocalStack, Plans documentation (March 23, 2026 changeover)
• CoddyKit, "GitHub Trending November 2026" (November 3, 2026)
• AI Frontier Post, "Run AWS on your laptop for free: hands-on with Floci"
• RepoRadar, floci-io/floci star history
• RateMorph, USD to GBP, November 9, 2026 (1 USD = 0.7471 GBP)
• RateMorph, USD to CAD, November 9, 2026 (1 USD = 1.4066 CAD)