Oleksandr Zotov, Developer in Lviv, Lviv Oblast, Ukraine
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Oleksandr Zotov

Verified Expert  in Engineering

Full-stack Developer

Lviv, Lviv Oblast, Ukraine
Toptal Member Since
June 18, 2020

Oleksandr is a developer with 11 years of experience specializing in development with C#, Angular, Python, and Unity. Oleksandr's developed fintech apps, constructed marketplaces, built the core apps for the biggest airline company in Europe by passenger count, Ryanair, and other complex solutions for a range of industries including air travel, financial, energy, and eCommerce. Some of the well-known brands that Oleksandr has worked with are Lionbridge, Qorvo, AO.dk, OneView Scada, and WebCRM.


Team International
Microsoft SQL Server, TFS, Angular, .NET Core
Amazon Web Services (AWS), Parallel Programming, Concurrent Programming...
Newfire Partners
CSS, TFS, HTML, Angular, Azure Service Fabric, .NET Core




Preferred Environment

Visual Studio, Windows

The most amazing...

...projects were building te fintech startup, Commitly, from scratch as well as the SCADA system for renewable power.

Work Experience

Senior Full-stack Developer

2020 - PRESENT
Team International
  • Gathered all the needed requirements from the BA and, in cooperation with team-mates, designed a set of web APIs and UI apps for the purpose of ordering materials from external and internal suppliers at Qorvo semiconductors.
  • Implemented apps using clean architecture principles, .NET Core, Angular 8, and with the extensive help from team members.
  • Provided the solution with CI/CD for all environments basing on the Azure DevOps Server.
Technologies: Microsoft SQL Server, TFS, Angular, .NET Core

Senior Software Developer

2018 - 2020
  • Took part in the development of flight scheduling and optimization apps for Ryanair which were made up of event-driven (NServiceBus) and domain-driven microservices and WPF plugin-based UI applications.
  • Contributed to the design of existing and new services, in particular, the audit service that gathers historical data from other services and web APIs for the pilot's mobile application.
  • Contributed to unit, integration, and functional testing using the TDD approach.
  • Wrote Groovy scripts (Jenkins pipeline) for the deployment of apps in different environments.
  • Helped the team to draw the solution from active development state to the production as well as the migration of existing apps from Azure infrastructure to AWS and from MS SQL to MySQL.
  • Performed technical reviews of my teammates' code.
  • Faced the daily challenge of the system's heavy load and very complex domain logic.
Technologies: Amazon Web Services (AWS), Parallel Programming, Concurrent Programming, Test-driven Development (TDD), Domain-driven Design (DDD), Groovy, MySQL, Microsoft SQL Server, NServiceBus, Azure, Windows Presentation Foundation (WPF), .NET Core

Full-stack Web Developer

2018 - 2018
Newfire Partners
  • Built microservices based on the Service Fabric for Lionbridge, the marketplace for professional translators. The main challenge was to provide reliability and scalability, as this platform serves translations of ~270 million words per month.
  • Enforced standards in the project to ensure software quality: GitFlow and pull-requests, clean code, best practices for logging, error-handling, and unit and integration testing.
  • Contributed to the UI development of a web app that connected translators with clients.
Technologies: CSS, TFS, HTML, Angular, Azure Service Fabric, .NET Core

Front-end Developer

2017 - 2018
  • Designed and developed from scratch front-end part of the fintech startup Commitly: a liquidity-planning application.
  • Taught and guided junior members of the front-end team.
  • Participated in scrum grooming sessions and the creation of tasks.
Technologies: Jira, HTML, Sass, Bootstrap, Angular

Freelance Web Developer

2015 - 2017
  • Developed turnkey basis websites using an existing graphic layout.
  • Negotiated deadlines and the budget with the client along with writing and coordinating technical tasks.
  • Contributed to various website projects: Helenbozhko.com.ua, Spadshchyna.org, Petlyuk.com, Boblox.org, and Bullimoto.com.
Technologies: HTML, SCSS, jQuery, Django, Python, Umbraco, ASP.NET MVC


2010 - 2015
  • Reworked the API for the CRM platform (Web CRM) to the newer technologies—from MS Access database and COM services to WCF MS SQL-based services which improved stability and maintainability of the system. Also wrote unit tests.
  • Developed new features and maintained the old functionality on both the front and back ends of the website AO.dk: a wholesaler of technical materials and tools in Scandinavia. Alos wrote unit and functional tests to improve overall reliability.
  • Worked within the team that redesigned AO.dk—worked on the order creation process, integration with payment system, sign-in and register logic. Improved speed of order creation and ease of use. Changes were deployed to production.
  • Maintained the existing functionality in OneView, which is a SCADA system for renewable power plants. Implemented drivers for new turbine types. The drivers collect, unify, and analyze data from turbines.
  • Added the visual editor-constructor for wind turbine controllers in OneView SCADA, so that they be able to see analytic data in the most convenient and custom way.
  • Wrote forecasting algorithm for the power output based on the existing data and set of additional input parameters—wind speed and direction, time of the year, temperature, and more.
Technologies: R, Microsoft Silverlight, HTML, CSS, jQuery, ASP.NET, Windows Communication Foundation (WCF), C#


2009 - 2012
IUDICO (University Project)
  • Took part in the implementation of the SCORM-compliant learning management system (LMS) called IUDICO—constructing with the plugins paradigm. The system is currently used by the university to test student performance.
  • Designed and developed curriculum and course management subsystems (plugins) in accordance with the teacher's inquiry.
  • Covered functionality with the unit and integration tests.
Technologies: CSS, HTML, NUnit, Castle Windsor, Entity Framework, ASP.NET MVC

Ryanair ROCS

I developed core applications for Ryanair, the biggest airline company in Europe by passenger count. These applications work under a high load of 19,000 employees and 45 million requests per month to the main website. I worked on FTL (flight time limitations) and Optimizer (automatic crew allocation by flight that complied with EU airline rules). I also maintained the current logic, implemented a new one, added unit, integration, and functional tests using a TDD approach, was responsible for the deployment scripts, and did tech reviews.
The system was made of a set of domain-driven and event-driven microservices and a WPF UI application made for crew controllers. Initially made on Azure and MS SQL infrastructure, we migrated it then to AWS and MySQL. Also, I designed and implemented a web API that was used by the main mobile application for cabin crew and pilots. I also developed the audit microservice which collected and presented the historical data from the other services.


The fintech startup Commitly built a liquidity planning application. I was the first front-end developer of the app and built it from scratch. I implemented the UI using Angular 4, Bootstrap, Sass, and HTML. We worked under the scrum methodology and as it was the startup, the main challenge was to understand business needs and the given graphic layout and then transform all of it into a flexible, scalable design and do it in a short time-frame. About a month after the start, they added a new front-end developer who I also mentored. After 11 months of development, we released the MVP.


Lionbridge is the marketplace for professional translators. Its back end has a microservice-based architecture built on top of the Azure Service Fabric platform.
The main business goal was to provide a sufficiently available, scalable, and flexible platform as it translates about 270 million words per month and is used by more than 1 million people. We achieved this by using Service Fabric features as well as smart partitioning and data replication.
I was responsible for the creation and maintainability of the services and the enforcement of the best practices for logging, error-handling, testing, and repository structure while following clean code principles. I also implemented the UI part of the application which was served as the bridge between translators and customers.


This system was designed for renewable power plants that gather data from turbines using specific drivers, sorts the information, stores it in an internal database, and provides a data analysis for the turbine operators on the UI.
My tasks were to maintain and improve both the back- and front-end sides of the application. I also wrote design documents, implemented new drivers and analysis modules, and improved the UX of the UI app.
Technologies: WCF, Silverlight, R
2018 - 2020

Master's Degree in Innovation and Entrepreneurship

LvBS | Lviv Business School of UCU - Lviv, Ukraine

2007 - 2012

Master's Degree in Applied Mathematics and Informatics

National University Ivan Franko - Lviv, Ukraine


Entity Framework, jQuery, NServiceBus, MediatR, Material 2, Azure Blob Storage API


xUnit, MSTest, Jira, TFS, Git, Amazon Simple Queue Service (SQS), Amazon Elastic Container Service (Amazon ECS), Amazon Cognito, Amazon CloudWatch, Azure Key Vault, AWS Fargate, Visual Studio, Microsoft Silverlight, Castle Windsor


.NET Core, NUnit, Bootstrap, ASP.NET MVC, Angular, Windows Presentation Foundation (WPF), Unity, Django, ASP.NET


C#, HTML, CSS, JavaScript, TypeScript, R, YAML, Groovy, Sass, Python, SCSS


FluentValidation, REST, Design Patterns, Test-driven Development (TDD), Concurrent Programming, Parallel Programming


Software Design Patterns, Azure, Umbraco, Azure Service Fabric, Azure Functions, Docker, Amazon EC2, Amazon Web Services (AWS), Windows


Microsoft SQL Server, MySQL, Amazon Aurora, Amazon S3 (AWS S3), Azure SQL, MongoDB


SOLID Principles, SOAP, Domain-driven Design (DDD), Windows Communication Foundation (WCF), Azure Service Bus, Groovy Scripting

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