Open-Source

This is a cross-post. I wrote this up for the dev.to audience. For the full architecture, benchmarks, and SDK compatibility numbers, read the in-depth write-up here on the site: Introducing Floci. Floci’s ~24 ms startup is not one clever trick. It is four battle-tested open-source projects stacked on top of each other, each doing the job it does best: Netty for high-performance async I/O. Vert.x for the reactive, event-driven toolkit. Quarkus for the application framework and build-time optimization. GraalVM Mandrel to compile the whole thing to a native binary. Together they take startup from the 2 to 6 seconds a typical JVM app needs down to ~24 ms, and idle memory from a few hundred MiB down to ~13 MiB. The honest takeaway is that this speed is borrowed: years of production hardening in those libraries are what let Floci spend its own effort on the part that matters, AWS protocol fidelity across 45 services and 1,925 SDK compatibility tests (Java, Python, Node.js, Go, and Rust). ...

This is a cross-post. I wrote this up for the dev.to audience. For the full architecture, benchmarks, and SDK compatibility numbers, read the in-depth write-up here on the site: Introducing Floci. “Java” is not the answer people expect for a tool that has to feel instant. But the choice was made on constraints, not taste. Floci needs to cold start in milliseconds, idle in single-digit MiB, and ship as one small binary that drops cleanly into a CI pipeline. Java 25, compiled with Quarkus and GraalVM, hits all three: a ~24 ms cold start, ~13 MiB idle memory, and a single ~90 MB binary. Modern features like virtual threads let it juggle many AWS services concurrently without ceremony. ...

This is a cross-post. I wrote up the design philosophy behind Floci for the dev.to audience. For the full architecture, benchmarks, and SDK compatibility numbers, read the in-depth write-up here on the site: Introducing Floci. Most AWS emulators make you pick a side: fast-but-fake (shallow mocks that pass your unit tests but never catch real integration bugs) or heavy-but-faithful (a giant container that boots in seconds and eats hundreds of MiB). Floci refuses that tradeoff. ...

This is a cross-post. I wrote this up for the dev.to audience. For the full architecture, benchmarks, and SDK compatibility numbers, read the in-depth write-up here on the site: Introducing Floci. Persistence is exactly the kind of feature emulators love to lock behind a Pro tier. In Floci it is free, and it is configurable. You get four storage modes and you can set them globally or per service, so each service gets the durability versus speed trade-off that actually fits your workload: ...

This is a cross-post. I wrote a shorter, community-friendly intro to Floci for the dev.to audience. If you want the full architecture, benchmarks, and SDK compatibility numbers, read the in-depth write-up here on the site: Introducing Floci. The short pitch: LocalStack Community Edition started requiring auth tokens and moved features behind paid tiers in early 2026. Floci fills that gap, a free, open-source, MIT-licensed AWS emulator that starts in ~24ms, idles at ~13 MiB, runs on the same port 4566, and never asks for an account, token, or quota. ...

In late 2019, the Java world was buzzing with a new name: Quarkus. Promising “Supersonic Subatomic Java,” it aimed to fix the long startup times and heavy memory usage that had plagued traditional Java applications in the age of containers and serverless. At that time, Quarkus was still in its BETA phase, but the vision was clear. It wasn’t just another framework; it was a fundamental rethink of how we build Java applications for Kubernetes. ...

In the world of modern data architectures, Change Data Capture (CDC) has become a cornerstone for building reactive, event-driven systems. At the heart of this movement is Debezium, a distributed platform that turns your existing databases into event streams. Joining the Stream In July 2020, I had the opportunity to contribute to the Debezium project. My involvement came at a time when I was deeply immersed in building real-time data pipelines and realized the power of capturing row-level changes without overloading the source databases. ...

Looking back at my career, one of the most rewarding chapters was the time I spent as a Linux Administration instructor at Fundación Código Libre Dominicano. This journey began in 2006, following what the foundation recognized as an “outstanding study” period where I deeply immersed myself in the world of Unix-like systems. By 2007, I transitioned from student to instructor, a role I would hold until 2012. Building the Foundation Teaching at FCLD wasn’t just about showing people how to use a terminal; it was about fostering a mindset of freedom and technical sovereignty. My students were often professionals or aspiring sysadmins looking to break away from proprietary stacks and embrace the power of the GPL. ...

Floci is a suite of local cloud emulators that let you run AWS, Azure, and GCP services on your own machine, with no accounts, auth tokens, or usage limits. Every emulator is built with Quarkus, compiled to a native binary with GraalVM Mandrel, starts in ~24 ms, and idles around 13 MiB. Everything is MIT-licensed and free forever. The name comes from cirrocumulus floccus, a small, fluffy cloud formation. That’s the design goal: minimal, lightweight, and always free. ...

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. ...