Lucas Frederico

AWS Certified

Building Minecraft servers that hold 1,500 concurrent players without breaking a sweat.

Concurrent users on a single JVM shard

ms p95 hot-path latency

years of recovery-under-60s SLO

years on the JVM

GitHub LinkedIn s0urce_ Email

About

A decade of Java. Half of it on Minecraft.

I started with my own Minecraft servers a decade ago, learning Java the hard way, fixing my own crashes at 2am while 200 players waited.

Today I do it professionally. Five years deep into Spigot/Paper/Purpur, building production-grade plugins for LoverCraft, a network running up to 1,500 concurrent players. Before that, five years shipping enterprise Java/Angular systems for Kinross Gold, Grendene, and Olfar.

NMS-deep performance and remapping work
Cross-server Redis architectures (pub/sub, distributed locks, runner election)
Anti-dupe systems and packet interception via ProtocolLib
World-per-island engines with SlimeWorldManager + FAWE
Production debugging at 2am, the kind that only comes from running it live

Certified

AWS Cloud Practitioner

Foundational · Amazon Web Services

// what I optimize for

throughput: "main-thread safe",

consistency: "network-wide",

recovery: "< 60s on incident",

audit: "every coin movement logged"

Open source

Three projects I'd put on a résumé.

fanloop v0.1.0 · MIT

Self-hostable real-time fan-out gateway. Spring Boot + Redis pub/sub backplane for cross-replica delivery with no sticky sessions. Helm chart, Kustomize overlays, ArgoCD app-of-apps with kube-prometheus-stack and a committed Grafana dashboard. Terraform module provisions the AWS platform (VPC, EKS, ElastiCache, ArgoCD bootstrap). CI deploys the full stack to a kind cluster and runs a cross-replica smoke test.

Java 25 / Spring BootKubernetes + ArgoCDTerraform

Real-time fan-out · K8s + GitOps end-to-end · CI on kind

github.com/lucasfrederico/fanloop

tickloop v0.2.1 · MIT

Real-time JVM toolkit in Java 21. Tick-based scheduler with main-thread safety guarantees, MPSC backpressure queues with four overflow modes, percentile histograms (p50/p95/p99), multi-rate TickGroup, virtual-thread offload pool. Includes a Spring Boot 4 starter and a JMH benchmark module. Anonymized extraction of patterns I ran in production for five years.

Java 21MPSC queuesJMH

Real-time JVM toolkit · 53 tests · CI matrix Java 21+23 · Linux + macOS

github.com/lucasfrederico/tickloop

pgcraft v0.1.0 · MIT

lazygit-style TUI for PostgreSQL. Schema browser, SQL editor, EXPLAIN view, pg_stat_user_tables and pg_stat_activity views, live filter. Postgres-only by design. Public Docker image on GHCR, multi-arch (amd64 + arm64), CI green on Linux and macOS.

GoBubble TeaPostgres internals

Postgres TUI · multi-arch Docker · keyboard-driven

github.com/lucasfrederico/pgcraft

Also shipped:

slow-query-watcher — Spring Boot 3 and 4 starter that auto-logs slow JDBC queries with full context (SQL, parameters, caller stack, transaction id). Drop the dep, set a threshold, done. JavaSpring Boot
pg_table_bloat — PostgreSQL extension in Rust (pgrx 0.13) that estimates table bloat from pg_class and pg_stats without pgstattuple. CI matrix Postgres 14 to 17. RustpgrxPostgres
django-multi-tenant-demo — Reference implementation of multi-tenant Django with queryset-filter isolation, audit triggers via signals + thread-local, JWT auth. PythonDjango

Production work

Live multiplayer platform at 1,500 concurrent.

LFAuctionHouse

Cross-server marketplace, rewritten from 2,800 lines of legacy JS into a clean Java system, and the foundation for two pieces of network-wide infrastructure.

PaperCustom ORMRedis

LFSkyBlockCore

The core gameplay system powering the network's SkyBlock gamemode: world-per-island, real-time cross-server sync, and a full plugin ecosystem on top.

PurpurNMSSlimeWorldManager

LFSBMines

Private mine system with custom mobs, animated 3D models, live block regeneration, and per-player stat tracking, fully integrated into the SkyBlock core.

PaperModelEngineMythicMobs

All projects

Plus seven more, shipped to production.

LFPlayerProfile

Network-wide player profile with stats, emotes, badges, and LuckPerms-driven roles.

PurpurLuckPermsMySQL

LFMail

Cross-server mail system for staff broadcasts, reward delivery, and player-to-player messages with attachments.

PaperMySQLRedis

LFGifts

Player-to-player gifting system with full send/receive history and per-server config.

PaperMySQLRedis

LFRTP

Random teleport with custom biome zones and full Bedrock support via Floodgate + Cumulus forms.

PaperFloodgateRedis

LFSeasonalResetVault

Cross-season vault that persists items through resets, with capacity upgrades and item banlists.

SpigotMySQLDecentHolograms

LFPlaytime

Tracks player playtime across servers with milestone rewards, leaderboards, and AFK detection.

PaperMySQLPlaceholderAPI

LFLeaderboards

Pluggable leaderboard engine with both Hologram and Citizens NPC rendering, plus a PlaceholderAPI expansion.

PaperCitizensPlaceholderAPI

LFReferral

New-player referral system with reward queueing, async reminders, and reference-way tracking.

PaperMySQLJoda-Time

LFCustomChests

Auto-selling chests with item whitelists, trusted-player ACLs, and tiered upgrades. Integrates with the network shop and AuctionHouse.

PaperMySQLShop API

SkyBlock Ore Generator

Custom ore-generation engine for the SkyBlock gamemode: tiered generators, weighted block tables, and per-island upgrades.

PurpurNMSMySQL

Enterprise experience

Five years of enterprise Java. Five of plugins.

LoverCraft LLC · Senior Backend Engineer · Freelance

Mar 2021 - Present·Remote

Senior backend engineer on a 3-to-5-person team running a US-based real-time JVM platform that sustains up to 1,500 concurrent users on a single shard, with sub-50ms p95 on the hot path and a recovery-under-60s production SLO held across 5 years. Worked across bug fixes, new features, and architecture: cross-shard state via Redis pub/sub, idempotent operations with full audit trails, JVM tuning, declarative infra (Ansible + Docker + Vagrant), CI/CD on GitHub Actions and GitLab, Grafana SLI/SLO dashboards. Domain: live multiplayer platform (Minecraft network) with 30+ network-wide services.

Stack: Java · Spring Boot · Spigot/Paper/Purpur · NMS · MySQL · MariaDB · MongoDB · Redis · Docker · Ansible · Vagrant · GitHub Actions · GitLab CI · Grafana · SonarQube

Senior Sistemas · FullStack Developer II · Software Factory

Apr 2021 - Feb 2024·Blumenau, Brazil

Full-stack development for major enterprise clients. Tech leadership on a fixed team, rotating into other squads as needed for surge work and senior technical decisions.

Kinross Gold (international gold mining): Third-Party Management system with HCM/ERP integration; monthly billing controls; Budget Management system for corporate budget oversight
Olfar: Lab Management system (sample tracking, label printing)
Grendene: Workforce Allocation system
Also: Flutter mobile applications.

Stack: Java · Spring Boot · Angular · Flutter · Docker · Oracle · MySQL · SQL Server · Maven · GitLab CI/CD · SonarQube · JIRA

Senior Sistemas · FullStack Developer I · Solution Factory

Nov 2019 - Apr 2021·Blumenau, Brazil

Full-stack development for legacy and new clients.

Stack: Java · Angular · Docker · MySQL · SQL Server · Maven · GitLab

Senior Sistemas · IT Intern · Software Factory

Jan 2019 - Nov 2019·Blumenau, Brazil

Full-stack on new features and bug fixes: Spring Boot, Angular, Git, Maven. Joined the "Equipe de Ouro" recognition team.

Stack

The full toolbox.

Languages

Java10 years

Go2 months

Python6 months

TypeScript5 years

JavaScript7 years

Backend

Spring Boot6 years

Spring Framework6 years

Maven7 years

Gradle3 yearsREST Web ServicesLombok7 years

Platform / DevOps

Docker7 years

Kubernetes2 months

Helm2 months

Kustomize2 months

ArgoCD2 months

Ansible1 year

Git10 years

GitHub Actions5 years

Prometheus6 months

Grafana5 years

ClickUp3 yearsVirtual Machines5 years

Cloud / Deploy

AWS3 years

Railway1 year

Databases

PostgreSQL5 years

MySQL7 years

MariaDB6 years

Redis5 years

Messaging

Redis Pub/Sub5 years

AI Agents

Claude Code8 months

Live Multiplayer Platform (LoverCraft domain)

Spigot8 years

Paper8 years

Purpur8 yearsNMS8 yearsProtocolLib8 yearsFastAsyncWorldEdit7 yearsSlimeWorldManager3 yearsMythicMobs3 yearsModelEngine3 yearsPlaceholderAPI5 yearsLuckPerms5 years