Zsolt Rácz, Developer in Budapest, Hungary
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Zsolt Rácz

Verified Expert  in Engineering

Software Developer

Budapest, Hungary

Toptal member since May 11, 2020

Bio

Zsolt has over 10 years of experience in full-stack development, mainly with Angular, Node.js, and Symfony. With his deep engineering knowledge, leadership experience, and holistic approach, he provides extraordinary value and understands what it takes to build stable, robust tools for extremely high-traffic use (e.g., 18 million monthly users for a video-on-demand service). Recognized as a team player, Zsolt considers himself a quick learner motivated by challenges.

Portfolio

Proximus
GraphQL, Jenkins, Electron, Jasmine, Node.js, Angular, HTML5, jQuery...
iflix
Amazon Web Services (AWS), Kubernetes, Redis, Docker, PostgreSQL, NestJS...
Kendaxa Development
Magento, Docker Compose, Symfony, PHP, API Design

Experience

  • SQL - 10 years
  • JavaScript - 9 years
  • Angular - 6 years
  • REST APIs - 6 years
  • PHP - 6 years
  • Node.js - 6 years
  • Symfony - 5 years
  • TypeScript - 3 years

Availability

Part-time

Preferred Environment

REST APIs, JavaScript, Angular, Symfony, TypeScript, Node.js

The most amazing...

...project I've worked on was iflix (iflix.com), a video streaming platform with more than 18 million active users.

Work Experience

Senior Engineer

2020 - PRESENT
Proximus
  • Contributed to the development of a desktop application for the customer support of Belgium's largest telco. Worked in an agile team, delivering new features and bug fixes.
  • Created a responsive front end from scratch based on UI mockups. The application is used by the customer service department to support millions of clients.
  • Set up and maintained development pipelines in GitLab to improve the team's efficiency.
  • Conducted over 10 technical interviews and developed the screening process and technical exercises.
  • Liaised API interfaces between corporate teams in the role of a technical analyst. Documented and passed info about the services to developers. Also took part in implementation, code review, and automated testing.
Technologies: GraphQL, Jenkins, Electron, Jasmine, Node.js, Angular, HTML5, jQuery, Agile Software Development, Scrum, TypeScript, SCSS, Technical Hiring, API Design

Software Engineer

2018 - 2019
iflix
  • Participated in the development of a video-on-demand service with more than 18 million monthly active users.
  • Collaborated with an agile team on subscription and payment management while cooperating with engineering teams distributed worldwide as a software engineer on the project.
  • Designed and implemented an order queuing system to support high load scenarios exceeding 80 transactions per second.
  • Implemented new microservices for integration with external partner APIs.
Technologies: Amazon Web Services (AWS), Kubernetes, Redis, Docker, PostgreSQL, NestJS, TypeScript, Node.js, API Design

Software Developer

2018 - 2019
Kendaxa Development
  • Led the API development of a shift planning tool used by a German telecommunications product distributor with 700 employees.
  • Collaborated with the product owner and suggested improvements for the long-term vision, leading to a 30% reduction of development time and a 50% reduced server load.
  • Suggested and implemented improvements in the security, performance, and architecture of the application.
  • Participated in the development of smaller eCommerce projects.
Technologies: Magento, Docker Compose, Symfony, PHP, API Design

Web Developer

2016 - 2017
Ticketware SE
  • Participated in information system analysis, design, and development based on PHP, Symfony 2, Doctrine, and Angular 2.
  • Created a mobile application for ticket scanning through a bar code reader or camera. The application was developed using NativeScript and Angular 2 and supports Android and iOS.
  • Developed a comprehensive comparison of cross-platform mobile technologies based on the selected core technology for the project.
  • Built software for content distribution and playback on display panels in cinemas.
Technologies: Symfony, PHP, Angular, NativeScript, TypeScript, JavaScript, Node.js, API Design

Web Developer

2014 - 2016
Maxi Mark
  • Architected and implemented a fitness center management system that generated a turnover of €1.5 million in the first year.
  • Created over ten dynamic and responsive websites, all of which were custom-tailored by a graphic design expert.
  • Set up the internal company server and introduced the use of version control.
Technologies: Bootstrap, jQuery, JavaScript, PHP, Symfony

Web Developer

2011 - 2013
eN Net
  • Constructed, using PHP, MySQL, and JavaScript, five websites for various businesses.
  • Managed the administration of Linux-based web servers running 30 websites.
  • Set up and maintained a gaming portal and game servers for hundreds of players.
  • Implemented network monitoring and an alerting system using Nagios.
Technologies: Nagios, Apache2, Debian Linux, JavaScript, MySQL, PHP

Experience

Website and E-shop for TAM Autohof

https://autohof.sk/en
TAM Autohof is a network of petrol stations in the Czech Republic and Slovakia.

I was in charge of the solution design and implementation of their website. Eventually, an e-shop was added to the website. It was integrated with the company's customer reward system and handled orders from thousands of registered members.

The site is built on PHP and Symfony; WordPress handles the CMS functionality and administration interface.

OnlineFit: Fitness Center Management Application

https://www.onlinefit.sk/en
OnlineFit is a comprehensive, multilingual web application that helps fitness center owners manage their businesses. Fitness owners can generate their websites and let their customers easily sign up for training through a calendar.

As the full-stack engineer, I designed the entire architecture of the solution and provided operations and support for over a year.

Main features of the system:
Booking management for group training, online payments, invoicing, stock management, website creator, support for multiple clients in different locations, and built-in business analytics tools.

Emplaya: Workforce Management Tool

Emplaya is a tool for managing the workforce of mid-to-large size companies. Its main features include shift, vacation, and sick leave planning. It consists of a desktop and a mobile application. I participated as the lead developer of the microservice-based API providing a back end for the desktop and mobile application. My roles included providing maintenance, implementing new features to the back end, documenting processes, and internal API documentation.

Beyond - Mobile Application Back End

For the Beyond mobile application, I designed and implemented a sophisticated back-end architecture to manage the app's core functionality, which allows users to record and schedule the release of audio and video content for future dates. The challenge was building a solution that could handle large media files, ensure long-term storage, and stream them efficiently using adaptive bitrate technology.

Except for back-end responsibilities, I also supported the front-end development team, providing guidance and troubleshooting across the iOS and Android platforms to ensure a cohesive and efficient user experience. From advising on media handling to API design, I played a critical role in bridging the gap between the back-end services and the mobile app’s functionality.

MAIA - Web Interface for ChatGPT-based AI Tool

I worked as a front-end developer on MAIA, an AI assistant for a telecommunications company. The tool, built with Node.js, TypeScript, and Angular, allowed call center and shop agents to quickly retrieve information from a knowledge base. I played a key role in technical analysis and development, including analyzing dependencies, documenting API calls, and designing a data storage solution for an analytics tool (data warehouse). Additionally, I wrote all user stories, ensuring a structured development process.

Education

2015 - 2017

Master's Degree in Informatics

Technical University of Košice - Košice, Slovakia

2012 - 2015

Bachelor's Degree in Informatics

Technical University of Košice - Košice, Slovakia

Skills

Libraries/APIs

Node.js, HTTP API, REST APIs, Google Maps API, Doctrine 2, jQuery

Tools

Postman, Git, NGINX, Jira, Confluence, Nagios, Jenkins, Amazon Simple Queue Service (SQS), Docker Compose

Languages

HTML, HTML5, PHP, JavaScript, CSS, SQL, TypeScript, C++, C, GraphQL, Java, SCSS

Frameworks

PHP MVC, Express.js, Symfony, Angular, NativeScript, Ionic, NestJS, Bootstrap, Laravel, Qt, Jasmine, Electron, CodeIgniter

Paradigms

RESTful Development, Agile Software Development, Metaprogramming, Scrum

Storage

JSON, PostgreSQL 10, MySQL, Redis, Amazon S3 (AWS S3), PostgreSQL

Platforms

Docker, Linux, Debian Linux, Apache2, Magento, Kubernetes, Amazon Web Services (AWS), WordPress, Azure

Other

API Integration, APIs, Web MVC, Third-party APIs, Web Development, Front-end, API Design, User Interface (UI), Software Design, UML Diagrams, Task Management, Networks, WebSockets, cURL, API Testing, Software Engineering, Engineering, Technical Hiring, tampermonkey

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