Senior Full-Stack Engineer

Designing scalable, secure, high-performance web and cloud platforms

Developer portrait
Developer working

About Me

Senior full-stack engineer and software architect specializing in React and Next.js. I design and ship scalable applications with a focus on performance, developer experience, security, and maintainability.

I have deep experience with API contracts (tRPC/REST), state management (Zustand/TanStack Query), data layers (PostgreSQL, Drizzle ORM), authentication (NextAuth, Better Auth), and CI/CD on Google Cloud (Cloud Build/Run/SQL).

I lead technical direction, set code standards (ESLint/Prettier), and implement observability plus release processes in Turborepo monorepos.

Work Experience

Development Engineer & PDF Specialist

01/2025 – Present
Foxit
Slovakia · Remote

Leading Tagged PDF School (PDF Association) on Next.js + tRPC hosted on Google Cloud, integrating C++ validation engines, and running CI/CD plus monitoring for a mission-critical PDF education platform.

Next.jstRPCGoogle CloudPDF SDKC++Observability

Software Engineer

10/2023 – 01/2025
Foxit
Slovakia · Remote

Delivered web and cloud components, automated quality checks, introduced ESLint/Prettier standards, and strengthened CI steps across teams.

ReactTypeScriptGitESLintCloud Applications

Junior Software Engineer

07/2022 – 10/2023
Foxit
Slovakia · Remote

Built C++/Python tooling, integration modules, and cross-platform builds for PDF workflows.

C++PythonCross-platform builds

Quality Assurance Engineer

11/2020 – 07/2022
Foxit
Slovakia · Remote

Owned testing strategy, automation, scenarios, and reporting across PDF products.

QA AutomationTest StrategyReporting

Founder & Lead Engineer

2020 – Present
Nexelon s.r.o.
Slovakia · Remote

Tech lead for bespoke products—architecture, full-stack delivery, client communication, infrastructure, security, and SLAs.

Tech leadershipArchitectureClient deliveryCI/CD

Developer

06/2020 – 09/2020
HIMA
Nitra Region, Slovakia

Developed FLOWorX pipeline system with leak detection in C++/Qt and modular extensions.

C++QtSystems design

Key Competencies

Architecture & System Design

Designing modular monorepos with domain modeling and API contracts, reducing technical debt and accelerating developer onboarding.

Performance & Scaling

Optimizing applications via SSR/ISR, caching, and code-splitting, improving LCP by 40–60% and reducing infrastructure costs.

Security & Auditability

Implementing secure auth flows, audit logs, and sensitive data handling, ensuring compliance and reducing data breach risk.

Developer Experience

Establishing automated CI/CD, strict linting, and release processes, cutting code review time by 50% and increasing delivery speed.

Re-platforming & Migrations

Leading re-platforming initiatives that reduce codebase size by 20–35% and accelerate build/deploy cycles while maintaining functionality.

Technology Stack

Frontend

Next.js
React
TypeScript
Tailwind CSS
Shadcn/UI
Zustand
TanStack Query
Responsive Design

Backend

Node.js
tRPC
PostgreSQL
Drizzle ORM
NextAuth.js
Better Auth
Serverless
API Design

Tools & Infrastructure

Git
Docker
Turborepo
Google Cloud (Cloud Run/Build/SQL)
CI/CD
Monorepo

Additional Technologies

C++
Python
Electron
Qt
Stripe Integration
AI Integration
Cypress
Testing
Observability

Featured Projects

Tech lead, architect, and full-stack engineer delivering custom products including infrastructure, security, and SLAs.

Responsibilities

Define architecture, domains, and delivery plans for both greenfield and re-platforming initiatives.

Lead client communication, roadmap prioritization, and shared code standards across teams.

Operate CI/CD on Google Cloud with automated testing, observability, and release guardrails.

SplitWallet

SplitWallet

Expense-sharing platform with real-time sync, offline UX, and premium features backed by Stripe. Extensive automated E2E tests in Cypress.

Next.js (App Router)tRPCPostgreSQLDrizzle ORMZustandTanStack QueryTailwind CSSCypress
View Project

Selected Projects

Tempora – Attendance & Leave

http://tempora-demo.nexelon.sk/

B2B attendance system with check-ins/outs, vacation approvals, reporting, roles, and audit log. Extensive automated E2E tests in Cypress.

Impact: Modular domains with server actions, optimistic updates, caching, and accounting exports.

Next.js
Tailwind CSS
Drizzle ORM
PostgreSQL
tRPC
Better Auth
Cypress

Inventory & Billing – Bakery

Re-platform from Node.js + Express + vanilla stack to Next.js + Styled Components to unify FE/BE delivery.

Impact: Higher type safety, faster time-to-feature, and reliable invoice/stock movement printing.

Next.js
Styled Components
TypeScript
PostgreSQL

Delivery Notes – Electron + React

Desktop app with local storage, offline UX, sync modules, and robust printing.

Impact: Guaranteed offline workflows for field teams while keeping data consistent across devices.

Electron
React
TypeScript

Warehouse Management – Creative Agency

Platform for material intake/issue, pricing, documents, and role-based access on Next.js + Drizzle.

Impact: Secure role-based operations with auditable exports and predictable deployments.

Next.js
Drizzle ORM
PostgreSQL
tRPC
Tailwind CSS

SplitWallet Case Study

SplitWallet application screenshot
SplitWallet UI detail
SplitWallet UI detail
SplitWallet UI detail

Project Overview

SplitWallet is a sophisticated expense-sharing application that helps teams track, manage, and reconcile group costs. Users can create wallets, capture expenses, monitor balances, generate reports, and settle debts efficiently.

Technical Highlights

  • Monorepo built with Next.js, tRPC, PostgreSQL, Drizzle ORM, and Turborepo.
  • State sync system with offline operation, background revalidation, and conflict resolution.
  • AI-powered receipt processing using Gemini 2.5 Pro and PDF export tooling.
  • Debt minimization algorithms with multiple settlement modes and guardrails.
  • Comprehensive design system with accessible light/dark modes.

Key Features

  • Expense management with configurable distribution models per user/group.
  • Wallet hierarchy with permissions, invitations, and contextual insights.
  • Real-time updates, offline support, and transparent sync states.
  • Localization, multi-currency, and automated reminders.
  • Premium functionality backed by Stripe subscriptions.

Architecture Principles

  • Security best practices in auth/session flows, auditing, and handling sensitive data.
  • Modular domains with clearly defined boundaries and responsibilities.
  • Accessible, localized UI built on a consistent design system.
  • Code standards and conventional commits for predictable and maintainable codebase.

Selected Achievements

  • Re-platformed multiple products to Next.js, cutting codebase size by 20–35% and speeding up build/deploy loops.
  • Standardized Turborepo setups and Google Cloud CI/CD pipelines (Cloud Build + Cloud Run).
  • Designed Drizzle data models with safe migrations/rollbacks and automated release gates.
  • Established reliable release processes with linting, tests, and preview deployments on every change.

Languages

SlovakNative
EnglishB2 – professional working proficiency

Get In Touch

Open to new products, architecture reviews, or leadership engagements for scaling engineering teams.