But It's Not a 13MB Go Binary Running The Entire AWS Cloud

Someone just open-sourced the entire AWS cloud in 13 MB. Every local AWS emulator before this needed gigabytes of RAM. Cold starts took 30 seconds just to test one function.   A team just open-sourced Floci. It's a single Go binary that runs the entire cloud in memory.   The whole footprint is 13 MiB. The average Chrome tab uses 200x more than that.   It boots 45 services in under a second. Point the standard SDK at localhost and existing scripts work untouched.   What runs locally with zero dependencies:   > S3, Lambda, DynamoDB, SQS > IAM, KMS, Cognito, STS > Step Functions, EventBridge, CloudFormation > API Gateway, Kinesis, Secrets Manager   No daemon, no Python runtime, no Java VM.   Pre-built binaries ship for Linux, macOS, and Windows. Tests finish before LocalStack Pro pulls its Docker image. The repo is 100% open-source with no paid tier.

Floci is real, but the LinkedIn post gets several key facts wrong:

Wrong

• "Go binary" — Floci is written in Java, using Quarkus and compiled to a native binary with GraalVM Mandrel, not Go.Floci is a free, open-source local AWS service emulator written in Java using Quarkus and compiled to a native binary via GraalVM Mandrel. Hector Ventura
• "13 MB is the whole footprint / entire cloud in 13MB" — 13 MiB is the idle memory figure for the native binary, not the binary size and not "the whole footprint." its published 13 MiB figure is idle memory rather than binary size, and the actual native executable is roughly 40 MB, with the Docker image around 90 MB.Native binary · ~40 MB WavectGitHub
• "No daemon, no Docker, zero dependencies" — misleading. Many services (Lambda, RDS, ECS, EC2, EKS, MSK, etc.) actually run as real Docker containers, not lightweight in-process mocks. Many control-plane services run in process, while Lambda, RDS, ECS, EC2, EKS, MSK, OpenSearch and others use Docker-backed engines. The official recommended install path is via Docker. Wavect
• "45 services" — sources vary (35, 47, 68/69, 75 depending on the date checked), but none put the complete AWS catalog on the table — it's broad but partial coverage, and the number has been climbing as the project matures. its canonical matrix listed 68 emulated services on 26 July 2026, not the whole AWS catalog Wavect

Roughly right

• MIT licensed, no paid tier, no auth tokens — accurate. No auth token, no restrictions, ever. Floci
• Fast startup — real, ~24ms native cold start, genuinely much faster than LocalStack's ~3.3s. Startup time · ~24 ms · ~3.3 s GitHub
• Drop-in SDK compatibility on localhost:4566 — accurate, it deliberately mirrors LocalStack's port/protocol so existing scripts work untouched.

Context missing from the post: Floci emerged specifically as a reaction to LocalStack's Community edition which introduced authentication requirements and feature restrictions in March 2026 — it's a competitor project, not some anonymous "open-sourcing of AWS." Anavem

So: cool project, real speed/memory advantages over LocalStack — but the "Go," "13 MB binary," and "zero dependencies/no daemon" claims in that post are inaccurate embellishments, likely from viral LinkedIn engagement-bait rather than the project's own docs.