Work

MVS Global Pools

A pool company in Greenstone, Johannesburg, working across the country: construction, renovation, leak repairs, pumps and weekly maintenance. Founded in 2014, eleven staff. A national outlet profiled the founder in February 2026, and anyone who read it and went looking found a Facebook page, because there was no website and no domain. That gap was the entire pitch.

One page, built around 22 photographs they supplied, with no prices on it. Every pool is a different quote, so the page explains why there is no price list rather than inventing a starting number. Enquiries arrive at an address on their own domain.

It started as a cold pitch nobody asked for. It is now a paying client on a monthly, so the hosting, the DNS, the email routing and any changes are mine to run. The domain is registered in their name, not mine, which is where it should stay.

You've been professional, helpful, and patient throughout the process, and I really appreciate the effort you put into understanding my business and creating a website that represents MVS Global Pools professionally. I would definitely recommend your services to anyone looking for a reliable and professional web designer.

Madodana Vodloza, Founder, MVS Global Pools

Open the site (opens in a new tab)

Silver Lakes Marketplace

A resident-to-resident marketplace for a Johannesburg gated estate, built with a co-founder. Auth, listings, offers, in-app messaging with live updates, wishlists, seller ratings, and an admin panel for category moderation, reporting and takedown.

Card payments run on Paystack subaccounts with a server-side split: an item's price settles straight into the seller's own bank account and only the service fee reaches the platform. The transaction is initialised server-side and the browser only resumes it, so the amount and the split can't be edited in devtools. Every table is row-level- security locked to its owner, and the migrations are tracked in the repo rather than only in a dashboard.

Live at the domain below since 29 August 2026.

Open the site (opens in a new tab) Code (opens in a new tab)

Faircopy

Paste a client's messy brief and get back a proposal you can edit, save and export. Handed a brief with no budget, no scope and no deadline, it opens with the three questions it needs answered and marks itself provisional, rather than inventing a number. Billing, quotas, webhooks, credit grants and PDF export all work.

The demo needs no account and no API key: it runs on fixtures and touches no database, which is why it is never the part that is down.

I finished it and then stopped selling it. Proposal tooling for freelancers is a crowded market where customers churn the moment they land the contract that made them sign up. Nothing failed technically. It is here as work, not as a product.

Open the demo (opens in a new tab) Code (opens in a new tab)

Syzygy

A small planet you roll a marble around, in the browser. Gravity points at the centre of the planet instead of downwards, so there is no floor and no edge: roll in one direction for about fourteen seconds and you arrive back where you started. Five monuments stand unlit on the surface: the four projects below, and one that is how you reach me. Light all five and dawn breaks over the whole planet.

25 modules, roughly 7,000 lines, and one image file in the entire repository. No build step, no package.json and no game engine. The terrain, the sky, the monuments, every piece of in-world type and every sound are generated at runtime. Collision is hand-rolled sphere against sphere and sphere against capsule, and the ground is an analytic sum of sines, so it can be sampled without touching the mesh.

Open it (opens in a new tab) Code (opens in a new tab)

Kohi by Ifuku

A coffee shop, micro-gallery and jazz kissa at 44 Stanley in Johannesburg. Menu, hours and directions, built to load instantly on a phone in the queue. Still mine to maintain.

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Vivarium

A personal, non-client artificial-life simulation. A free simulate loop runs every five minutes with no LLM involved: grazers and hunters in a predator-prey relationship, terrain, a day-night cycle. Separately, a guardrailed evolve loop calls Claude Code CLI a few times a day to propose one real code change to the simulation's own rules.

The interesting part is the guardrail engineering, not the ecosystem content: a working pattern for letting an LLM modify its own codebase without needing to trust it, because every constraint is enforced in code rather than asked for in the prompt. Evolve can only write three paths, a diff cap measured against the actual changed lines, not file length, holds it to 900 lines and 8 files a run, and a daily budget caps it at three runs. The 17-test suite has to pass before anything commits. A rejected or failing proposal is reverted whole, never partially applied.

Seven evolve runs so far, one landed. Four were rejected by a guardrail bug that measured proposed files' full length instead of the real diff, making success mathematically impossible until it was caught and fixed on 2026-09-04. One failed to parse as JSON, one was reverted when a fix broke on a test that didn't model real terrain. The one that landed gave grazers a camouflage gene: it shrinks a hunting hunter's effective sense range specifically against that grazer, and grazers now visibly fade toward the background in proportion to it.

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Lumen

A site system for wedding photographers. One codebase, one config file per client, and a location page per town generated from an array, so a new client site went live in an afternoon instead of a fortnight.

Roughly 90 approaches to photographers, nine to venues, no closes. The build was never the problem. I was selling to people spending their own money on something they had already decided they could do without, which is the same mistake I had made twice before.

The write-up The page it sold from

BidForge

Another run at proposal writing for freelancers, and the same buyer as Faircopy. Same answer. The repository is private, so there is nothing here to open.

Dev Blog

A blog layout built around a measured 66-character reading column. No infinite scroll.

Demo (opens in a new tab) Code (opens in a new tab)

Snapfolio

A single-page portfolio for portrait and creative photographers. Near-white, black type, colour only in the photographs.

Demo (opens in a new tab) Code (opens in a new tab)

ZenSlide

A landing page for yoga and wellness studios. Warm stone and sage.

Demo (opens in a new tab) Code (opens in a new tab)

williammcilleron.netlify.app

Hand-written HTML, CSS and JavaScript. No build step, no package.json, no framework and no dependencies, so there is nothing in it that can rot while I am not looking. The contact form runs through one Netlify function.

The fonts are self-hosted and subsetted from 215KB to 74KB, done by dropping variable-font axes rather than characters, and the commands to redo it sit in a comment at the top of the stylesheet. It loads in about a second on a phone with bad signal, which is the whole reason for building it this way.