Gabor Koos

Full Stack / Backend Engineer

I design and build scalable, maintainable, high-performance digital experiences for the web.

About Me

I'm a Hungarian software engineer with 10+ years of experience, currently located in London. I specialize in designing and building scalable, high-performance web applications, with a strong focus on clean architecture, maintainable code, and efficient backend systems. I was working for companies like the Daily Mail, Capgemini, Betsson Group, Racing Post and Origo (one of the largest newsportals in Hungary). I hold a Master's Degree in Mathematics and Computer Sciences.

Throughout my career, I've worked with a wide range of technologies and frameworks, contributing to projects in various industries including fintech, online gaming, e-commerce and SaaS.

Over the years, my tech stack has evolved significantly. I started my career working mostly with PHP, building dynamic websites and custom CMS solutions. As the web ecosystem matured, I transitioned into JavaScript and later TypeScript, working on full stack applications using modern frameworks such as React, Node.js, and Express. More recently, I've been focused on Go (Golang), leveraging its performance and concurrency strengths to develop scalable microservices and backend APIs.

I have a strong interest in cloud technologies and DevOps practices, having worked with AWS, Docker, and Kubernetes to deploy and manage applications in production environments. I believe in the importance of writing clean, maintainable code, and I'm always looking for ways to improve development processes through automation and best practices.

I'm passionate about solving complex technical challenges and continuously improving development workflows and system reliability.

Experience

  1. 2024 - 2025

    Maintain and improve the company's proprietary Real Time Analytics solution. Record and save every user interaction on every Daily Mail website and banner ad, and present them in a meaningful way in customisable charts and pivot tables etc. via a dashboard app to Operations and Editorial. Feed all the data to a ML solution. Design, implement and optimise features in RESTful APIs and gRPC services for seamless communication with microservices and external services.

    • Microservices
    • Typescript
    • Node.js
    • Golang
    • MySQL
    • Elasticsearch
    • Redis
    • Kafka
    • gRPC
    • REST
    • AWS
    • GCP
    • Docker
    • Kubernetes
    • CI/CD
  2. May 2022 - 2024

    Collaborate closely with clients across diverse projects to thoroughly understand their business goals and technical challenges. Engage in detailed discussions to define problem specifications, translate requirements into scalable system architectures, and lead the design and implementation of effective, maintainable solutions tailored to each client's unique context.

    • Typescript
    • Javascript
    • Node.js
    • React
    • Next.js
    • Redux
    • Redux Toolkit
    • Recoil
    • Electron
    • Golang
    • Vercel
    • Netlify
    • Redis
    • MongoDB
    • DynamoDB
    • MySQL
    • Postgres
    • REST
    • GraphQL
    • AWS
    • GCP
    • Azure
    • Contentful
    • Docker
    • Kubernetes
    • Terraform
    • CI/CD
  3. Jan - Apr 2022

    Develop a SaaS platform in a team for effectively handling invoices in foreign currencies. Design and implement a robust backend system using Node.js and Google Cloud Functions, ensuring high performance and scalability. Create a user-friendly frontend with React, enhancing the overall user experience.

    • Javascript
    • Node.js
    • React
    • Redux
    • Redux Toolkit
    • REST
    • GCP
    • CI/CD
  4. 2020 - 2022

    Develop, maintain and extend the company's payment platform, called YAP. Integrate new payment service providers and implement new payment methods for existing PSP's. Ensure PCI compliance, make changes to the payment flow according to legal requirements (3DS, SCA, etc.) Manage upstream and downstream dependencies, assist the various organisations within the company with their custom requirements and payment related queries

    • Javascript
    • Node.js
    • React
    • MySQL
    • Redis
    • AWS
    • CI/CD
    • Kibana
  5. Jun - Nov 2019

    Tech lead for a team of 5 developers. Develop the company's rolling credit product in typescript (Node backend, React frontend) following BDD and DDD methodology, integrate it with various e-commerce platforms. Do migrations and maintenance work on the company's legacy PHP platform.

    • Javascript
    • Typescript
    • Node.js
    • Express
    • Postgres
    • MongoDB
    • React
    • AWS
    • PHP
    • Symfony
    • CI/CD
    • Docker
    • Kubernetes
  6. Jan 2018 - Jun 2019

    Rewrite the monolithic Drupal application serving supercasino.com, jackpot247.com and vernons.com in a microservice architecture with Angular in the frontend and Node.js and some php in the backend. Implement GDPR with Playtech and Betsson's own backend solution called Techsson. Internal / admin pages frontend with React. Maintenance and bug fixing in Drupal.

    • Microservices
    • PHP
    • Drupal
    • Laravel
    • Javascript
    • Typescript
    • Node.js
    • Express
    • React
    • MongoDB
    • ETCD
    • AWS
    • Docker
  7. Jun 2014 - Jan 2018

    Work on a variety of development projects and delivering solutions to external and internal clients. Assist in maintaining the company's Sybase stored procedure codebase. Alter the Zend Engine core C code to effectively handle multiple Sybase database connections. Software development for terminals in betting shops. Display in an embedded (Chrome based) browser, written in Angular1.4 (some parts in typescript).

    • PHP
    • Zend Framework
    • C
    • Phalcon
    • Sybase
    • Oracle
    • Javascript
    • Angular
    • jQuery
    • D3
    • Redis
    • RabbitMQ
    • Vagrant
  8. Oct 2013 - Jun 2014

    Lead a small team of developers working on the gold trading platform of the company. Handle concurrency to accurately and effectively calculate rates, commissions etc.

    • PHP
    • Javascript
    • Node.js
    • Express
    • MongoDB
  9. Jul - Oct 2013

    Build and integrate a test automation framework into the company's development workflow (unit, functional and end to end tests). Magento development.

    • PHP
    • Magento
    • Javascript
    • Selenium
  10. March 2012 - Jun 2013

    Develop mobile applications, work on various backend projects (database migration from Oracle to MySQL, introducing nosql solutions like Redis, Memcached and MongoDB) for Origo, the biggest online portal in Hungary.

    • PHP
    • MySQL
    • Oracle
    • Redis
    • MongoDB
    • Memcached

Featured Projects

  1. 2024

    Data sampling for RTA (Real Time Analytics)

    Implement a data sampling solution for the Real Time Analytics platform, which collects and processes user interactions on Daily Mail websites and banner ads. The solution is designed to handle high volumes of data while ensuring that the most relevant trends are captured for analysis. The sampling solution is built using Typescript and Node.js, and it integrates with the existing Real Time Analytics platform. It uses a combination of statistical techniques and heuristics to select a representative sample of user interactions, which are then processed and stored in a scalable manner.

    • Typescript
    • ElasticSearch
    • OAuth2
    • Node.js
    • Redis
    • REST
  2. 2023

    CornerShop

    AI-enabled store staff solution to help customers find products in a supermarket, using a mobile app and a web dashboard for store staff. The app uses AI to understand the user's intent and provide relevant product information, while the dashboard allows store staff to manage customer requests and provide assistance.

    • Javascript
    • React Native
    • GCP
    • Firebase
    • OpenAI API
  3. 2023

    Quest for Hope

    Develop a game on Roblox to raise awareness of the plight of endangered species and the importance of conservation.

    • Javascript
    • Roblox Studio
  4. 2022

    BP self-service order and payment

    Create a proof of concept Electron app to order and pay for food, fuel and car wash, running on proprietary hardware for BP.

    • Typescript
    • React
    • Redux
    • Electron
  5. 2020 - 2021

    Cannes Lions membership / payments

    Integrated payment solution for every Cannes Lions product.

    • Typescript
    • Node.js
    • Express
    • React
    • MySQL
    • Elasticsearch
    • Redis
    • AWS
  6. 2018

    Netplay backend

    Complete rewrite of the Netplay casino sites (supercasino.com, jackpot247.com, vernons.com) in a microservices architecture from a monolithic Drupal application. GDPR implementation. Playtech and Betsson integration.

    • Typescript
    • Node.js
    • Koa
    • Angular
    • MySQL
    • ETCD
    • Docker Swarm
    • PHP
    • Drupal
    • Laravel
  7. 2017

    Racingpost integration in BGT betting terminals

    Enable proprietary Racing Post content on 12000+ self-service betting terminals within multiple UK operator retail betting estates - responsible for the backend and some frontend work. Implementation of some Racing Post API calls, full intergation with the RP B2B API. Horse and greyhounds race predictor and some of the bet prompts on the frontend.

    • Javascript
    • Angular
    • Sybase
    • PHP
    • Zend Framework
  8. 2015 - 2016

    Generate all reports and feeds for Racingpost B2B and website

    Rewrite of Racing Post's legacy content delivery system in a scalable, distributed way. Implement a proprietary monitoring system.

    • PHP
    • Python
    • Sybase
    • Redis
    • RabbitMQ
    • Javascript
    • Bash

Testimonials

  1. Scott Ronan

    Scott Ronan · Head of Technology at Betsson Group

    Whilst I worked with Gabor he demonstrated a strong understanding of web and software development with good attention to detail. Diligent and helpful I would work with him again.

  2. Preetam De

    Preetam De · Scrum Master/Agile Coach

    Gabor, while working in my Scrum team in Betsson group, emerged as an exceptional developer with vast knowledge to back up his wisdom. Always curious to find out the root cause of issues and business outcome validity. He is very professional and fit right in on any team he works with. He will be a great asset to every team who needs a trusted member to rely on.

  3. Paolo Casani

    Paolo Casani · Senior Developer

    I have had the pleasure to work closely with Gabor while at the Racing Post. He joined a core project that I had been working on for a few months. Immediately, he hit the ground running, taking ownership and developing very sophisticated but neat solutions. Gabor is a really outstanding and very talented developer. At the Racing Post he was well known for completing in a matter of a few hours tasks that took others many days. Having played professional basketball as a younger man, Gabor is of course a very good team player and has a jovial character. I can only strongly recommend him.

  4. Robin Doran

    Robin Doran · Deputy IT Director

    It was a pleasure working with Gabor. He was key member of our development team.