Andrej Guran, Developer in London, United Kingdom
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Andrej Guran

Verified Expert  in Engineering

Software Developer

London, United Kingdom
Toptal Member Since
December 15, 2020

Andrej is the ex-CTO of and Roombles and an ex-partner engineer at Facebook. Andrej has a track record of delivering high-quality products tightly aligned with business and market needs, defining and driving the engineering strategy, and fostering an environment of ownership, innovation, and technical excellence.


PHP, Laravel, Amazon Web Services (AWS), MySQL, React, React Native, APIs...
SQL, PHP, React Native, React, APIs, REST APIs, Python
Amazon Web Services (AWS), Amazon Elastic Container Service (Amazon ECS)...




Preferred Environment

Docker, Elasticsearch, Redis, Symfony, Laravel, Vue, React, MySQL, PHP 7, Amazon Web Services (AWS)

The most amazing...

...thing I've developed was a horizontal marketplace with integrated payment and logistics that was the fastest growing marketplace in Germany in 2018.

Work Experience


2021 - PRESENT
  • Developed a React Native app that combines experiences of TikTok and Groupon.
  • Built the scalable architecture on AWS Cloud and utilized the Laravel framework to create an API that powers the mobile apps.
  • Worked on the whole project (built under 100 days) and from idea to launch in just under three months.
Technologies: PHP, Laravel, Amazon Web Services (AWS), MySQL, React, React Native, APIs, REST APIs

Partner Engineer

2019 - 2021
  • Integrated various partners (Shopify, PayPal, SumUp, Square) to a new Facebook initiative (Local Gift Cards) that helps small businesses affected by COVID. Gave technical guidance and built internal tools to accommodate the various needs of partners.
  • Built technical solutions to unlock partner potential and scale growth and integrated high-value sellers in the EMEA and NA region for Instagram Checkout (H&M, Zara, L'Oreal).
  • Worked closely with the engineering teams to deliver Facebook Shops: a new shopping solution from Facebook.
Technologies: SQL, PHP, React Native, React, APIs, REST APIs, Python


2016 - 2019
  • Led the development of a marketplace model eCommerce project with a focus on the RESTful API.
  • Assembled a team of six developers and coordinated the work of 12 remote mobile developers.
  • Responsible for the back-end and front-end development and the infrastructure of the whole project.
  • Set up the development processes and workflows and applied Agile methodologies.
  • Delivered a high-performance, durable, and scalable architecture that handled a large number of visitors while continuously enabling the high pace of change and innovation.
  • Utilized the AWS infrastructure, Elasticsearch, Redis, MySQL, and message queues.
Technologies: Amazon Web Services (AWS), Amazon Elastic Container Service (Amazon ECS), Docker, Elasticsearch, Redis, MySQL, Laravel, PHP, React Native, HTML, CSS

Senior Software Engineer

2014 - 2016
Rocket Internet
  • Worked as a core developer in cross-functional teams for various international companies with millions of customers.
  • Launched ventures from concept to production while meeting strict deadlines.
  • Created Nestpick's platform to search apartments in the biggest rental aggregator.
  • Integrated a solution for Foodpanda's AAA partners (McDonald's, Pizza Hut, Domino's Pizza, and KFC).
  • Built Everjobs: a career-listings platform for international markets.
  • Optimized, for Skyscale, Rocket’s core marketplace system Alice&Bob used by Zalando.
  • Developed Burger King Germany's food delivery solution based on the Foodora codebase.
  • Implemented performance and load testing for and Foodpanda.
Technologies: Git, NGINX, RabbitMQ, PHPUnit, Redis, Elasticsearch, MySQL, JavaScript, PHP, HTML, CSS

PHP Developer

2013 - 2014
Currys PC World
  • Optimized the page speed and implemented a caching mechanism using Varnish for various e-merchant clients (A.P.C., Monnier Freres) resulting in an average 3x increase in load speed.
  • Implemented new features on an eCommerce solution for the largest electronic retailer in the UK: Currys.
  • Composed a new algorithm for category selection in the catalog that decreased the churn rate by 20%.
Technologies: Redis, Varnish, MySQL, PHP, HTML, CSS

Roombles | TikTok meets Groupon

At Roombles, I was responsible for setting technical architecture. I utilized ECS on AWS to ensure scalability and cost-effectiveness. The API was built using the Laravel framework v 8.0, which helped us be agile and very quick in implementing new features as well as following best practices and writing tests for the main parts of the application. With our CI/CD pipeline on GitHub actions, we delivered changes instantaneously to our users.

The mobile apps were written in React Native allowed us one codebase for both iOS and Android as well as an Agile roadmap. As a CTO, I was responsible for the whole architecture of the project from the infrastructure, through code approvals to KPI tracking, as well as leading a small team of three developers. | The Fastest Growing Secondhand Marketplace in Germany

As the CTO of and one of the first employees, I set the technical vision, proposed an architecture that would meet business goals, and hired a team of exceptional engineers.

Implementation of Multiple Core Features:
• Payment: Established the payment infrastructure that allowed the user to hold payments until the transaction was completed with the integration of all main payment systems.
• Notifications: Setup the framework that listened to system events and promptly notified users of action that needs to be taken through multiple channels (in-app notification, email, SMS).
• Logistics: Integrated this with the main carriers to allow for tracking packages and automatic tracking updates.
• DevOps: Scaled the infrastructure to handle loads during a TV campaign with peaks of 6,000 requests/second, the migration to AWS, and utilization of ECS. was a horizontal secondhand marketplace with the following main competitors:, Spock, and Facebook Marketplace. Our approach was to integrate payment and shipping to provide an eCommerce experience for secondhand shopping. became the fastest-growing marketplace in Germany and was acquired by Visable GmbH in May 2019.

Local Gift Cards on Facebook and Instagram

As a partner engineer, I was responsible for integrating with all major gift card providers in the EMEA region for the newly formed initiative—Local Gift Cards for Small Businesses—which was created within Facebook to help small businesses with financial relief during COVID-19 and lockdown.

My responsibility was to work closely with partners (gift card providers), understand their needs, and then build engineering solutions within Facebook and Instagram to accommodate their needs and help them accelerate sales on these channels.

This project's reach was over 20 million people within the EMEA region, and we helped over 13,000 local businesses struggling during the pandemic.

Burger King Germany | Delivery Service
I delivered a complete food delivery service for Burger King Germany. As a full-stack developer, I was responsible for implementing the primary features such as a restaurant search based on geolocation, the order management system, and integration to the restaurant's POS as well as building a front end that was aligned with the corporate identity of Burger King.

Nestpic | An Aggregator for Furnished Apartments
I built an aggregator for apartment listings similar to Airbnb. The main features included the following a search engine with a map and position of each apartment along with the ability to filter based on various criteria. It also was integrated apartment provider data sources and had lead tracking.

Integration of AAA Merchants into the Delivery Hero (Formerly Foodpanda) System
As a back-end engineer, I built an integration layer to import AAA merchants like Pizza Hut, Domino's Pizza, McDonald's, and Burger King into Foodpanda's (now Delivery Hero) restaurant and delivery system. This Integration abstracted all future possible integrations and provided plug-and-play capabilities for catalog and opening hours management as well as a full order-management service.
2011 - 2014

Bachelor's Degree in Applied Informatics

Masaryk University - Brno, Czechia


React, Vue, REST APIs


Amazon Elastic Container Service (Amazon ECS), RabbitMQ, NGINX, Git, Varnish


Laravel, PHPUnit, React Native, Symfony


Linux, Amazon Web Services (AWS), Docker


PHP, SQL, JavaScript, HTML, CSS, Python, PHP 7, Hack




MySQL, Redis, Elasticsearch


APIs, eCommerce, Architecture, Leadership, Full-stack, Web Development, ECS

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