01
Architecture
Service boundaries, schemas and migrations built to survive real users, real audits and the people who maintain them next. The diagram is the easy part.
- System design
- Data modeling
- APIs
Principal engineer · Charlotte, NC
Big systems.
Small details.
I design and ship software end to end — the architecture, the backend underneath it, and the operations that keep it honest.
01 / Expertise
Three layers, one system.
Not a project list — the three layers I spend most of my time in, and the seams between them.
02
Platform
The APIs, services and data behind the glass: GraphQL endpoints, event-driven jobs, ETL and the shared libraries other teams build on. The part nobody sees.
- Java
- Spring Boot
- PostgreSQL
03
Operations
Google Cloud, Kubernetes, CI/CD, observability and security — the layer you only notice when it is missing. Boring in production is the goal.
- GCP
- Kubernetes
- Terraform
02 / About
A short spec sheet.
Justin Baker
Principal Engineer
Charlotte, North Carolina
I am a principal engineer with fifteen years of building software for people who need it to work. Most of that time has been spent on public-sector systems — the kind where a migration has to be right the first time and a release has to be boring.
I like the whole arc: the whiteboard, the schema, the API, the migration, the pipeline, the pager. And yes, I still care about the details — usually the ones nobody sees.
- Role
- Principal Engineer
- Company
- Reason Consulting
- Experience
- 15+ years
- Based
- Charlotte, NC
- Cloud
- Google Cloud · Professional Cloud Architect
- Stack
- Java · Spring · React
- Elsewhere
- github.com/slayyyyer
03 / Projects
Things I built for the fun of it.
Twelve live experiments, each its own repository and its own subpath on this domain.
/jerlang/
An Erlang runtime for the JVM
Reads the BEAM files the Erlang compiler produces and interprets them on the JVM — processes, message passing, links, monitors and distribution written in Java, one reflective call away from Java code. OTP’s own gen_server and supervisor run unmodified, and the artifact is published on Maven Central.
- Java 21
- BEAM
- OTP 29
/clt-almanac/
The Charlotte Almanac
A daily weather note for Charlotte built on the station record back to 1939: ridge and logistic regressions retrained every morning, a backtest that only ever sees what was known that day, and a writer handed the finished numbers with orders not to invent any of them.
- Forecast model
- Backtest
- Charlotte
/buffy/
A desk pet for your coding agent
A tiny always-on-top companion for long coding sessions: Claude Code hooks, a repo watcher and a buffy CLI send thinking, working, needs-you and done to a daemon on 127.0.0.1, and an Electron overlay draws the pet. The daemon binds to loopback only, collects no telemetry and keeps its state in ~/.buffy; buffy hatch draws new sprites through the OpenAI Images API, and the Windows installer ships the app and its daemon together.
- Electron
- Node CLI
- Local daemon
/yahtzee/
Exact-probability Yahtzee
Play against a CPU that solves every roll with exact probabilities and keeps an exact table for the rest of the game, endgame included.
- Game
- Exact EV
/blackjack/
Blackjack Lab
An exact solver and the lab around it: a strategy chart that re-derives itself whenever a rule changes, plus card counting and a simulation target to prove the number.
- Solver
- Simulation
/murmur/
Murmur
A small animated face in Charlotte that reacts to weather, air quality, official alerts, river levels and earthquakes. A simulated mood, not a real one.
- Live feeds
- Character
/motobuzz/
MotoBuzz
Reads public motocross news, subreddits and rider and brand channels once an hour, then ranks what the sport is actually talking about.
- Ranking
- Hourly
/orders-service/
A three-repo reference system
One orders domain across three repositories: a Spring Boot 4 and Java 21 API with REST and GraphQL over Postgres 16, an RFC 9457 error model and a transactional outbox, recorded by CI rather than run as a live demo; six zero-downtime migrations measured against a busy writer; and Terraform verified against a mock provider, never applied.
- Spring Boot 4
- Postgres 16
- Terraform
/what-changed/
What Changed Today
A daily field-level diff of public records — Charlotte 311 service requests and the Federal Register — showing only what moved, with records labelled new, backfilled or aged out and a failed fetch published as no snapshot rather than a reassuring zero. Actions diffs, Pages serves: no server, database or keys.
- Daily diff
- Charlotte 311
- Federal Register
/word-chomp/
Word Chomp!
A garden word dig: unscramble six- or seven-letter racks, find the three-to-seven-letter words and clear every garden word before the 2:20 timer runs out. Vanilla HTML, CSS and JavaScript in one folder — no build step, no network request, original art and sound.
- Word game
- Vanilla JS
- No build step
/saf-explorer/
SAF Explorer
Opens MX Simulator .saf archives to list and extract what is inside, or packs a folder back into one. Pure Python standard library with an 11.5 MB standalone exe; extraction cannot escape the target folder, and a build writes to a temporary file before replacing the archive.
- Python
- .saf format
- Desktop
/mx-lab/
MX Lab: seven seasons, measured
One committed dataset of AMA Pro Motocross and Supercross results — seven seasons, 195 events, 17,434 result rows and 250,699 lap times — with six analyses published on top of it: lap chart, fade, lap one, qualifying, titles and an Elo rating per class. Rebuilds are byte-identical, and the gate fails the build on contradictions while recording source quirks as warnings that each name their sheet. Unofficial, derived statistics only: no source PDFs are stored or served.
- Node
- Dataset
- Static site
04 / Contact
Let’s make something solid.
If you are building something that has to last, I would like to hear about it. Email is best; GitHub is a good place to see what I am tinkering with.
jbakerdev199@gmail.com