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YK Développement
Full-stack developer · Available for new projects

Your idea deserves an exceptional web & mobile product.

Precise design, proven code, measured performance. And everything here can be checked: the demos load live, the shipped products run in production.

Estimate my projectSee shipped products
Proof before promises

The demos below are real: they load live, not as screenshots.

Shipped, and in production

Real products run daily, including a full SaaS.

One person, the whole chain

Design, code, data, launch: your project stays in the same hands.

The right tool for every layer:TypeScriptReact/Next.jsReact NativeRailsRustPostgreSQLThe whole chain, from systems languages to the interface

01 — Services

Four product families, demonstrated live.

Estimate a need

Sites, shops, web apps, mobile apps: every system below is designed and coded by YK Développement, and loads live. Pick the closest to your idea: in the quote builder, it adapts to your trade, your colours, your content.

Everything in the preview is real: browse, open, click.

Live — The Tableloading
Homepage of the The Table system
grammarWarm serifpalettestructure4 core sections · 4 modulespriceShowcase site — from €2,400YK Series — No. 02/25 · Designed & coded by YK DéveloppementEstimate my showcase site

Every system in this collection is designed, coded and maintained by YK Développement. No purchased themes, no off-the-shelf kits. And these are only the demos: the shipped products, running in production, are right below.

See the products in production

Yours could be next. An idea that looks like none of these? That's exactly the kind of project I like scoping best.

02 — Work

Complete products, from concept to production.

Five full-stack projects spanning web, mobile, desktop and R&D, designed, architected and built end to end. Three are shown in detail, two remain private.

In productionWeb SaaSMarketplacePayments

Mequi

Business SaaS connecting riders and equestrian coaches.

The equestrian world still largely runs on paper logbooks and scattered messages. Mequi brings geolocated matching between riders and coaches, session booking, progress tracking (goals, work plans, session reports), horse management, billing and subscriptions together in a single product, designed for two profiles with opposite needs and finished to consumer-grade standards.

Tech stack — 43 bricks
  • React
  • TypeScript
  • Node.js
  • PostgreSQL
  • Stripe
  • Playwright
Case study
Mequi project cover visual
TestFlightMobileiOSAndroid

Ceryo

All-in-one mobile app, smooth and offline-first.

Ceryo is a super-app: a modular mobile application bringing together planning, learning, a content library, real-time messaging, budget, health, travel and places, a rich editor and an AI assistant, all in an Apple-grade, fluid, offline-first experience where every screen must load instantly and behave like a system app.

Tech stack — 45 bricks
  • React Native
  • Expo
  • TypeScript
  • Ruby on Rails
  • PostgreSQL
  • Stripe
Case study
Ceryo project cover visual
ActiveDesktopRustTauri

GodMode

Native desktop cockpit for local projects and AI models.

Juggling several local projects (backends, frontends, workers) and LLM models loaded in RAM turns the command line into friction. GodMode is a unified control panel: a menu-bar icon plus a detailed window. One click to start, stop or restart a service; one shortcut to unload every AI model overheating the machine. Multi-project by design: what works for one project works for all, with no hardcoding.

Tech stack — 30 bricks
  • Rust
  • Tauri 2
  • Native IPC
  • React
  • TypeScript
Case study
GodMode project cover visual
PrivateBackendReal-timeR&D

Alpha

Real-time autonomous system: SSOT, runtime invariants, extreme robustness.

Alpha is a real-time autonomous system that I rebuilt entirely on a clean foundation. The project is private: I don't detail its functional logic, but it embodies the level of engineering rigor I carry into all my work, systematic root-cause fixing, zero cosmetic patches and verifiable safety nets.

Tech stack — 39 bricksSealed · NDA
  • Python
  • FastAPI
  • PostgreSQL
  • Rust
  • Tauri 2
  • Docker
View the project
Alpha project cover visual
PrivateAIMulti-agentR&D

Morpheus

The multi-agent testbed that shaped my real-time architecture.

Morpheus is an autonomous multi-agent engine, the R&D predecessor from which I distilled the architectural patterns later reused in my real-time projects. Private as well: I share its approach and engineering challenges, not its functional details.

Tech stack — 5 bricksSealed · NDA
  • Python
  • Multi-agent orchestration
  • MLX
View the project
Morpheus project cover visual

03 — The builder

You bring the idea. I build everything else.

An independent full-stack developer, I take your product on whole, from architecture to production. The person who scopes your project is the one who designs it, codes it, tests it and ships it: nothing gets diluted between vendors.

Demanding projects are my specialty. A mobile super-app, a complete business SaaS, autonomous systems in continuous service: each one runs in real conditions, and I still look after every one of them.

And the standard does not scale down with size. A few-page site gets the same seriousness as a critical system: it is the only way of working I know. Your project, whatever its ambition, will be treated that way.

Portrait of Yannis Koula

Founder — YK Développement

What guides me

Uncompromising quality
Every detail counts: accessibility, performance and pixel care.
Simplicity
The simplest solution that works, never over-engineering.
Transparency
Clear quotes, regular updates, no surprises.
Ownership
I take the problem end to end, from scoping to maintenance.

The whole chain, the same hands:

  • Architecture & languages
  • Web interfaces
  • Mobile apps
  • Back-end & APIs
  • Accounts & payments
  • AI features
  • Desktop apps
  • Testing & production
My background and the full skills map

04 — Method

A marked path, from idea to launch.

  1. Understand

    Your need becomes a written scope and a firm quote: you know exactly what will be built, and for how much.

    Discovery · Scoping & quote

  2. Craft

    Mock-ups first, then a product that advances in iterations: a demo at every step, never a tunnel.

    Design · Build

  3. Ship

    Full acceptance testing, production launch, handover of access and documentation: the product is yours.

    QA & acceptance · Launch & maintenance

The method in detail: what I do, what you receive

Ready to go from idea to product?

Get an estimate in under 4 minutes. No commitment.