ZEROFAYYZ STUDIOS

Marcel Gilbert
Full-Stack Software Engineer

I build applications, APIs, cloud systems and AI-enabled software — TypeScript, Python and PostgreSQL — and I test them like it matters. Twenty-one years leading technical teams in safety-critical aviation taught me that discipline; the deliverable is now code.

Stylised operations console for the ZEROFAYYZ FINTECH platform: payment lifecycle from checkout to ledger, test suites, CI pipeline, system health and audit trail
The platform's own surface — payment lifecycle, ledger, test suites, CI pipeline, system health and the append-only audit trail. Every figure on it is real: see the live dashboard.
Sixty-nine seconds, start to finish: a payment through hosted checkout, the signed webhook returning, the ledger updating, and the audit trail recording it. Recorded by the same Playwright suite that tests the platform; the narration is a synthesised voice.

Software

Deployed, tested, and open to inspection. Every claim below has a link behind it.

ZEROFAYYZ FINTECH — cloud payments & operations platform

Live · source public · Stripe sandbox, no real funds move

A payments platform built end to end and running in production: hosted Stripe checkout, signature-verified webhooks, an auditable PostgreSQL ledger, refunds under a four-eyes rule, and an operations console.

Problem
Payment systems fail quietly. A duplicate webhook double-credits an account, a ledger drifts from the truth, and nothing alarms — the damage is discovered in a reconciliation weeks later.
Architecture
One Fastify/TypeScript API over PostgreSQL, consumed unmodified by three independent frontends — Next.js, Vue 3 and Svelte 5 — each validating every response against one shared Zod contract at the network boundary. Bilingual, with translations enforced by the type system: a missing string is a compile error.
What I built
Idempotency enforced by a database constraint rather than application branching, so a redelivered webhook is refused under concurrency and across restarts. An append-only audit log the application itself cannot rewrite, enforced by a database trigger. Refunds that move the ledger only on the provider's signed event. An independent reconciler in Go — a checker sharing code with the thing it checks agrees with its bugs.
Testing & operations
341 automated tests across ten suites in ten CI jobs, including thirteen Cucumber scenarios that state the payment rules in plain language and execute. A QA surface an AI agent can drive over the Model Context Protocol. Monitored hourly in production by a 30-check suite whose webhook probe signs a real event — because a health endpoint reports that a signing secret is present, never that it is correct. I broke that secret deliberately to watch the alert fire, then restored it.
The defect worth citing
The webhook handler had nineteen passing unit tests and had never once worked. Every test replaced the database with a stand-in, so none executed the real SQL — and the SQL was invalid. The first integration test against real PostgreSQL found it immediately. A test suite has a shape, and defects collect where that shape does not reach.
TypeScriptNode · FastifyPostgreSQLNext.js Vue 3Svelte 5GoStripeZod PlaywrightCucumberDockerGitHub Actions

Try it: zerofayyz-fintech.vercel.app — click through in three minutes, everything is sandbox and safe to touch · source and thirteen decision records

Built for your company, if you need one: this is commissioned work as well as a portfolio piece — your provider, your ledger rules, your audit and compliance requirements. What carries over is the engineering above, not the branding: idempotency enforced by a database constraint rather than application branching, an append-only audit log the application itself cannot rewrite, refunds that move the ledger only on a signed provider event, and an independent reconciler. Scope and price depend on what you already have, and you will get a straight answer about whether it is a good fit. Ask what it would take →

Gabriel — desktop-class AI workstation platform

Built solo · private repository

A single React interface over conversational AI, local image generation, image-to-3D mesh conversion, voice synthesis, an animation studio, Blender and Unity integration, and a system-health lane that can inspect and repair the machine it runs on.

Scale
~24,000 lines of strict TypeScript and React 19 across 20 feature panels, over a Python and FastAPI backend of 39 REST endpoints with job orchestration and cancellation. Roughly 9,300 automated tests; 1,180+ commits.
The principle it is built on
Every operation that changes state writes an auditable record, and operations are allowlisted, sandboxed and reversible. A system that acts on a real machine should be verifiable, not trusted.
React 19TypeScriptPythonFastAPI Local LLM inferenceRAG · embeddingsMCP servers

fair-scan — a retrieval bug, extracted and fixed in public

Python · MIT · open source

A two-phase fair scan over a grouped document corpus, where group order never decides the result. Extracted from Gabriel's retrieval layer after I found a defect that made search answer confidently from the wrong source — no error, no empty result, just wrong, with a whole category of documents quietly unreachable.

The repository keeps the original broken implementation next to the fix and runs both on the same corpus, so you can watch it fail and then pass. Ten hermetic tests, zero dependencies, CI on three Python versions · github.com/marcelgilbertdev-oss/fair-scan

Free guides

Written because they did not exist and I needed them. No signup, no email gate, no upsell — read them, share them, feed them to your AI.

Digital products

Delivered from this site — downloads and reference works, free or paid. Nothing is listed until it exists and works: no pre-orders, and no launch dates that cannot be kept.

Tools & assets

Sold through the engine marketplaces rather than here, so that licensing, VAT and per-country tax are handled by the store a buyer already has an account with. This page will link straight to each listing when it is live.

Where these will be sold: the Unreal plugin and the asset packs on Fab, the Unity package on the Unity Asset Store, and the Blender add-on on Superhive. Nothing is listed yet, and there is no link above for that reason — this section exists so the route is obvious when there is, not to announce a date.

Stylised workstation showing the range of work: a web application dashboard, an API console, a 3D viewport with a rigged character, AI video generation, an automation pipeline, a CI pipeline and an append-only audit trail
The range in one frame — web applications and APIs, 3D and video pipelines, automated testing and CI. Illustrative of the kind of work, not a screenshot of a single product.

Creative technology & 3D

The same engineering applied to content pipelines. Tooling exists here because doing the work by hand did not scale — which is the reason to write any tool.

Asset pipelines & game-ready 3D

Blender · Python (bpy) · Unity · Unreal

Character rigging and skinning including retargeting onto an existing skeleton, named animation sets, LOD generation and export prep — automated with Blender Python I wrote, including a repeatable rig-transplant procedure that retargets a validated armature onto new meshes.

Why the engine check matters: FBX export can silently corrupt IK bones, and Blender's own importer will re-open the broken file looking correct. So every rig now ships with a parity test that runs in the target engine. That is the difference between an asset and an asset that works — and it is the same instinct as the integration test that caught the webhook bug above.

Generative media pipelines

Image · image-to-3D · video · voice

Local SDXL and FLUX image generation, image-to-3D mesh conversion, local video models and TTS voice synthesis, assembled through an ffmpeg pipeline into finished animated shorts. Model selection is most of the craft: the same prompt gives a usable shot on one model and garbage on another.

Public proof: the model-by-model prompting reference on this site is mine — around fifteen image and video models compared side by side, free and open. It is the working knowledge behind the production work.

Get in touch

Email reaches a person, not a queue, and you will get a straight answer about whether something is a good fit — including when it is not.

Whether you are:

  • Hiring — I am open to full-time software engineering roles, remote worldwide or Japan-based, and my CV and work history are on GitHub
  • Commissioning software — applications, APIs, cloud systems, AI integration, automation, debugging and test infrastructure
  • Commissioning 3D or creative technology — say which engine and what already exists
Email me → marcel.gilbert.dev@gmail.com