A focused partner for your next project

Apple expertise.
Full product delivery.

Our specialism is native iOS and macOS software, with security considered from the first architectural decision. We build new products, modernise established applications and take responsibility for technical delivery.

That focus is backed by experience in banking, media, real-time video and enterprise software. When a product needs Windows, Android, web or backend work, we can connect those parts too.

Tell us about your project Book a 30-minute call

What we build

Build, improve
and maintain.

Native iOS and macOS products, desktop software and internal tools, including subscriptions and paywalls
Legacy modernisation, performance improvements and recovery of delayed or unstable projects
On-device AI for document recognition, image analysis and workflow automation
APIs, ERP and CRM integrations, with Windows, Android and web development where the product needs it
Software architecture, application-security reviews and hands-on technical leadership

How we work

Close to the work.
Close to you.

Direct communication with the engineer responsible for delivery
A defined scope, budget and delivery plan
AI coding agents used throughout the development lifecycle, with engineering review and testing
Security considered throughout design and development
On-device processing where the application and hardware allow it

Selected engineering experience

Complex products. Concrete work.

Projects delivered by our founder across client and consulting engagements.

DRESSX

Native macOS · Real-time video

Digital fashion, live on camera.

A desktop camera application bringing real-time digital fashion into video calls.

Founder’s rolemacOS product architecture and hands-on implementation

The task: Apply digital fashion to a live camera stream and make the output available to conferencing applications without interrupting the call.
The work: Built a native capture and rendering pipeline, virtual-camera integration and an interface for controlling dynamically delivered visual effects.
The result: A desktop application that made digital looks usable in everyday video communication.

macOS
Video capture
Virtual camera

Dolby Laboratories

macOS · Computer vision

From imaging research to working software.

Advanced photo and video research prototypes using CoreML and Metal.

Founder’s roleLead macOS engineering for Dolby R&D through GlobalLogic

The task: Turn experimental imaging techniques into working macOS prototypes for a research team.
The work: Combined computer vision, CoreML depth estimation and image fusion with a Metal rendering engine for high-resolution video workflows.
The result: Working macOS prototypes for evaluating next-generation photo and video processing.

CoreML
Metal
Computer vision

Print Artist & Hallmark Card Studio

macOS & Windows · Modernisation

Established desktop software, rebuilt.

Modernisation of creative design and publishing applications with extensive existing content libraries.

Founder’s roleNative macOS implementation and Windows architecture in C# and .NET

The task: Rebuild mature design software while retaining editable documents, large artwork libraries and familiar printing workflows.
The work: Developed document and graphics models, visual editing, undo and redo, project persistence, asset search and print, PDF and image export.
The result: Modern desktop implementations that retained the document and publishing workflows expected by existing customers.

macOS
C# / .NET
Document editing

People who worked with our founder

Experience, in their words.

Read on LinkedIn

“I had the pleasure of working with Sergii at DRESSX, where he played a pivotal role in developing our camera app.”

Daria ShapovalovaCo-Founder, DRESSXLinkedIn recommendation · June 2024

“The testing resulted in a large number of security findings which he successfully fixed.”

Svetlana KilburnSenior QA Developer, HCSSLinkedIn recommendation · July 2024

“Based upon high level product requirements, Sergey is able to translate objectives into fully functional and tested deliverables within expected (agile methodology) timeframes.”

Dirk Van de PoelCPO & Co-Founder, KlarrioLinkedIn recommendation · May 2016

Agent-based SDLC

AI-assisted. Engineer-led.

We use AI coding agents across the software development lifecycle: understanding an existing product, planning changes, implementing code and supporting review and testing. Engineering judgement connects those stages.

Architecture, code review and release decisions stay with the engineer responsible for your product.

Understand
Establish the product goals, inspect the codebase and identify technical and security constraints.
Plan
Use agent-assisted investigation to prepare a scoped implementation plan and choose the architecture.
Build
Use coding agents for implementation and refactoring, with changes kept small enough to review.
Verify
Review the changes, run builds and relevant tests, and check security and actual product behaviour.
Release
Prepare the release, document decisions and maintain the product after delivery.

Read: renovating old iOS projects Read: building a macOS app with AI

AI-assisted development, demonstrated live

An empty project. A working iPhone app.

At the first Vibe Coding Luxembourg event, Sergii opened an empty Xcode project and let the audience choose the app and vote on its features. Using TRAE as the AI coding agent, he built an Earthquake Monitor prototype and ran it on a connected iPhone.

Read the event recap

Live prototype26 March 2026

Earthquake Monitor

House of Startups, Luxembourg

Live build: ~60 min
In person: 22
Online: 220

Live seismic data from an external source
Earthquakes displayed on a map
Alerts for seismic activity

The session demonstrated a working prototype with real data and an interface the audience could follow as it took shape.

Workshops & community

Building in front of an audience.

Explore the Meetup group

Our founder organises Luxembourg Vibe-Code & Hack Apps: practical sessions on AI-assisted development, app monetisation and application security. The sessions combine live demonstrations with questions from developers and product teams.

AI-assisted development

Build a real app with AI

26 March 2026

House of Startups · In person & online

A live build from an empty Xcode project to an Earthquake Monitor running on an iPhone, with the audience choosing features as the session progressed.

AI coding agents
Product structure
Live prototyping

Explore the live build

App monetisation · With Adapty

From free app to paid product

27 May 2026

Luxembourg · In person & online

A workshop with Adapty covering a premium feature, paywall implementation and a remote copy experiment, followed by pricing, paywall timing and conversion.

250+ participants

Subscriptions & paywalls
Remote experiments
Pricing & conversion

Read the workshop recap

Application security

iOS App Autopsy

5 May & 3 June 2026

Banking / FinTech & MedTech sessions

Live security analysis of production iOS applications using their distributed binaries. The sessions examined exposed secrets, hidden endpoints, configurations and SDK artefacts without access to source code.

Binary analysis
Mobile attack surfaces
Secure development

Read the MedTech session recap

Who leads the work

Sergii Koval

Founder · Principal Software Engineer & Product Architect

Kovallux is led by Sergii Koval, an engineer who works directly on architecture, implementation and delivery.

His experience spans mobile banking, media platforms, real-time video and enterprise applications. He combines Apple-platform engineering with mobile security assessments, threat modelling and the modernisation of established products.

Author of Secure Development of iOS and macOS Applications.

TRAE Fellow programme

Joined the TRAE Fellow programme in February 2026 as a community ambassador for Luxembourg, organising practical workshops on AI-assisted development.

Read the announcement

Meet Sergii on LinkedIn Explore the book

Where it can help

Built for real workflows.

Manufacturing: defect detection with iPad computer vision

Finance: document analysis for compliance workflows

Healthcare: local summaries of patient reports

Media: automated photo tagging and asset management

Based in Luxembourg. Working remotely with clients across Europe and the United States.

Read recommendations Selected projects Explore the book

Apple expertise.Full product delivery.

Build, improveand maintain.

Close to the work.Close to you.