Introducing Floci: The Fast, Free, and Open-Source AWS Emulator
Local development against AWS services has always been painful. You either run real AWS (expensive, slow, requires an internet connection) or use an emulator. For years, LocalStack was the go-to choice — until they required auth tokens and locked down their community edition in early 2026. That gap is exactly what Floci fills. Key Numbers: Native Floci vs LocalStack Metric Native Floci LocalStack Advantage Startup Time ~24 ms ~3,300 ms 138× faster Idle Memory ~13 MiB ~143 MiB 91% less Lambda Latency 2 ms avg 10 ms avg 5× faster Lambda Throughput 289 req/s 120 req/s 2.4× faster Price Free Forever Auth Token Req. $0 / No Auth What Is Floci? Floci is a free, open-source local AWS service emulator written in Java using Quarkus and compiled to a native binary via GraalVM Mandrel. It runs as a single process on port 4566 — the same port LocalStack uses — so switching requires zero changes to your existing code or tooling. ...