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Haidi Zakelsek

@haidizakelsek

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Product Engineer who builds scalable web apps at the product-engineering intersection.

Slovenia

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What I'm looking for

I’m looking for an autonomous, async remote environment where product thinking meets engineering. I want to own system design end-to-end, lead teams with clean-code standards, and build scalable web applications with strong testing and maintainability.

I’m a Product Engineer with 7+ years of experience designing and building complex web applications, translating user and business needs into clean, scalable architecture. I lead from scoping through deployment, and I communicate directly with clients and stakeholders to deliver aligned solutions.

I’ve worked across modern front-end ecosystems—React, Next.js, Angular, and Vue—plus backend and systems foundations with Node.js, ExpressJS, and databases like PostgreSQL. I’ve owned system design end-to-end, including reviewing and optimizing data models by consolidating fragmented entities and removing unnecessary joins.

Technically, I emphasize maintainability and quality: I define code quality standards, testing plans, and best practices, and I’ve built and optimized real-time UI experiences using WebSockets under high traffic. I’ve also introduced reusable component libraries and modular architecture patterns to reduce duplication and improve developer velocity.

I thrive in autonomous, async remote environments that value clean code and long-term maintainability. I’ve led technical teams of 3–5 engineers, mentored junior to mid-level developers through code reviews and 1:1 guidance, and served as a primary technical point of contact to keep product delivery on track.

Experience

Work history, roles, and key accomplishments

Senior Frontend Developer

Freelance

Jan 2023 - Jan 2026 (3 years)

Developed and maintained a high-traffic sports betting platform in React, building real-time WebSocket-driven UI components for responsive performance. Created reusable component libraries and testing coverage (Vitest/React Testing Library), reducing duplication and improving developer velocity.

React WebSockets React Testing Library Integration Testing Component Libraries Performance Optimization Cypress

Frontend Developer

AgileDrop d.o.o

Jan 2021 - Jan 2023 (2 years)

Developed web applications for multiple clients using PHP/Laravel and modern frontend frameworks (Vue.js, Angular, React, Drupal), including business sites, landing pages, and e-commerce. Served as primary client contact for requirement gathering and translated briefs into actionable development tasks to keep projects aligned with feedback.

PHP Laravel React Vue.Js Angular Drupal E commerce Development Client Site Requirements Task Management

Frontend Developer Intern

Intera d.o.o

Jan 2020 - Jan 2021 (1 year)

Contributed as one of the key engineers to build and ship a new admin dashboard for an enterprise CRM system supporting employee and finance workflows. Participated in architecture and development planning meetings with a team of 6 engineers.

Frontend Development Dashboards CRM Systems Architectural Participation Javascript Typescript Testing Awareness

Frontend Developer

Maestro Amadeus d.o.o

Jan 2017 - Jan 2020 (3 years)

Built core Angular features for a music-tech platform enabling musicians to organize sheet music and create playlists. Pitched the product to 10–15 investors and secured 3 years of funding, contributing to strategy, pricing, architecture planning, and UX direction.

Angular Product Strategy Architecture & Planning Landing Page Development Social Media Management

Product Engineer

Freelance

Jan 2026 - Present (5 months)

Led a team of 3–5 engineers across multiple SaaS projects, owning end-to-end technical architecture from scoping through deployment. Built a Next.js/Node.js/PostgreSQL web application for a municipality (Velenje) and mentored 4 junior/mid-level developers through code reviews.

React Next.js Node.Js Development PostgreSQL System Design Code Review Vitest

Education

Degrees, certifications, and relevant coursework

Faculty of Electrical Engineering, Computer Science and Informatics

Master’s degree, Computer Science and Informatics

2020 - 2023

Activities and societies: Delivered a free lecture on testing intelligent systems, covering metamorphic testing, property-based testing, and differential testing with live coding in Python.

Earned a Master's degree in Computer Science and Informatics at the Faculty of Electrical Engineering, Computer Science and Informatics.