// havox — v4

John Gatward

Software Engineer

Backend engineer by trade Full-stack developer by curiosity Unofficial family cloud engineer by necessity I like building useful things and figuring how they work.

see my work GitHub LinkedIn

about

Havox & me

day job

CS graduate from the University of Nottingham (2022), now working as a backend engineer at Sainsbury's Supply Chain & Logistics — building microservices with Spring Boot on AWS, designing REST APIs, connecting services with Kafka, and storing data in MongoDB.

home infra

I run a home server that hosts media and projects for friends and family. I enjoy building things that feel solid and useful — from small games like Crack the Quote to websites and services running on my own hardware.

linux

Long-time Linux user. Used to distro-hop obsessively and be deep in the ricing community — these days it's Hyprland on Void Linux and a growing collection of scripts that make the day job easier.

teaching

I tutored during school and university — CS, maths, English. Teaching stuck with me. Explaining things clearly is a skill, and it's why I also write tutorials here.

havox

Havox started as a place to document whatever I found cool — tutorials, visualisations, experiments. It's been running in some form since 2017, gone through four major redesigns, and outlasted several domains. It represents my entire journey through technology, and it's still going.

version history

Havox V4 — this one
2025 → present
Catppuccin Mocha. Single page. Trying to get a new job this time.
Havox V3
2023 → 2025
Borrowed a template. Nord theme. Took SCSS seriously. Considered mobile widths.
Havox V2
2019 → 2022
First SCSS project. First site on own hardware — a Debian box running nginx. Nord theme.
Havox.org
2017 → 2019
Entire site in one PHP file 🤣. Had a Python quote-of-the-day via cronjob though. Counts.

skills

What I know

☕

Backend

Professional Java experience building RESTful APIs with Spring Boot. Testing with JUnit & Mockito. Data persistence with MySQL, H2, JDBC.

Java Spring Boot REST JUnit MySQL
🌐

Frontend & Creative

JavaScript, p5.js, HTML/CSS/Scss. I enjoy visualising algorithms interactively — it's more fun than a console output.

JavaScript p5.js Scss HTML/CSS
🖥

Systems & Infra

Long-term Linux user. Self-hosted web & media servers. Comfortable with networking, security practices, and the command line.

Linux nginx Networking Self-hosting
🎓

Academic Breadth

C, C++, Haskell from uni. Coursework across Android dev, distributed systems, graphics, cryptography, malware analysis.

C / C++ Haskell Algorithms Security

tutorials

Things I wrote down

Best way to learn is to teach. When I find something interesting I write a short tutorial — mainly to consolidate my own understanding, but if it helps someone else that's a win.

3 Jan 2021 Summed-area tables Integral images — what they are, how they work, and why they're surprisingly useful for image processing. → 3 Feb 2019 Midpoint displacement terrain generation Generating random, natural-looking 2D terrains using the midpoint displacement algorithm. → 22 Sep 2018 Travelling salesperson Different implementations of the TSP problem — a classic that never gets old. → 14 Feb 2018 Convex hull generator Wrapping algorithms — visualising how to find the convex hull of a point set. →

projects

Things I built

Mostly p5.js — visualising algorithms in ways that look more interesting than they have any right to. Most use mouseClicked() so desktop only, sorry mobile.

1 Oct 2021 Drawing Bézier curves Interactive animated diagram for quadratic and cubic Bézier curves. Click to place points. → 23 Sep 2021 2D Marching squares Marching squares in action — click a tile to edit the terrain. → 11 Apr 2020 Bubble sort visualiser Bars sorted by height, one frame per loop. Classic. → 2 Apr 2020 Müller-Lyer illusion A visualisation of the Müller-Lyer optical illusion rendered in JS. → 27 Feb 2019 Fourier series Building a square wave from nothing but sine waves. Mesmerising. → 23 Feb 2019 Constructing an ellipse How an ellipse can be constructed with a circle and radial lines — inspired by 3Blue1Brown. → 2 May 2018 Game of Life A JS implementation of Conway's classic. Still fascinating. → 18 Mar 2018 Calculating PI Monte Carlo method — ratio of randomly placed dots in a square vs circle. → 17 Dec 2017 Oscillations in 3D JS implementation of a Bees and Bombs gif. One of my oldest. → 13 Nov 2017 Maze generator A maze generator in JS. The first project that made me think "oh, I like this". →

contact

Let's talk

I'm currently employed but open to the right opportunity — backend or full-stack, somewhere that ships interesting things with people who care about their craft.

GitHub has the most complete picture of how I think. LinkedIn if you're formal. Either works.

GitHub jayo60013 LinkedIn jaygatward