Grigory Zhadko, Developer in Valencia, Spain
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Grigory Zhadko

Bio

Grigory is a software engineer with over 15 years of expertise in back-end and desktop application development, primarily in C#. He led back-end development for w7g.tech, where he developed mobile games with up to 100,000 daily users. His work on the EPAM Systems platform allowed the daily rebalancing of fund investments for 10,000+ client accounts. Grigory has created CRMs, customer portals, and web applications for end users and has written documentation about codebases and infrastructure.

Portfolio

w7g
C#, .NET Core, Amazon Web Services (AWS), AWS Lambda, PostgreSQL...
Tawasal SuperApp
C#, PostgreSQL, LINQ to DB, ASP.NET Core, Sentry, Hangfire, SQL, .NET...
Logican Solutions
C#, Entity Framework, SQL Server 2016, Windows Presentation Foundation (WPF)...

Experience

  • C# - 15 years
  • Windows Presentation Foundation (WPF) - 7 years
  • Entity Framework Core - 5 years
  • PostgreSQL - 5 years
  • Amazon Web Services (AWS) - 5 years
  • .NET Core - 5 years
  • ASP.NET Core - 5 years
  • Hangfire - 3 years

Preferred Environment

Windows, JetBrains Rider, SourceTree, Git

The most amazing...

...work I've done is developing the back end of the #1 fashion game, supporting up to 100,000 daily users with high availability and scalability.

Work Experience

Lead Software Engineer

2020 - 2025
w7g
  • Built a fault-tolerant, high-performance back end using .NET and AWS, enabling smooth real-time gameplay and monetized features such as live events and in-game purchases, contributing directly to player retention and revenue.
  • Optimized performance through async processing, Redis caching, and database tuning, ensuring low latency and high availability during new feature rollouts and peak user activity.
  • Lowered infrastructure costs while maintaining reliability by proactively monitoring AWS usage and refining deployment architecture, improving the team’s cost-efficiency, and freeing budget for feature development.
  • Redesigned CI/CD pipelines, reducing deployment time by over 70%, which accelerated the delivery of revenue-generating features and supported frequent live content updates.
  • Enabled business growth by supporting scalable reward systems, flexible user segmentation, and reliable progression tracking—key components for increasing player engagement and monetization.
  • Managed and scaled a remote back-end team, establishing engineering workflows and fostering strong cross-functional collaboration across time zones.
  • Mentored engineers through regular 1:1s, code reviews, and pairing sessions, contributing to professional growth and raising the overall technical bar.
  • Created a culture of ownership and accountability, which enabled the team to ship features reliably and respond quickly to product demands.
Technologies: C#, .NET Core, Amazon Web Services (AWS), AWS Lambda, PostgreSQL, Entity Framework Core, NUnit, Moq, Hangfire, SQL, .NET, REST APIs, Microservices, APIs, ASP.NET, Windows, Git, Amazon Simple Queue Service (SQS), REST, Docker, API Development, Back-end Development, Architecture, Cloud, Database Design, Microservices Architecture, RESTFul APIs, WebSockets, Redis, API Design, Back-end, GitHub, Technical Leadership, Bug Fixes, C#.NET

Senior Software Engineer

2020 - 2020
Tawasal SuperApp
  • Contributed to the back-end development of Tawasal, a secure multi-purpose messenger and super-app offering voice, chat, video conferencing, and lifestyle services.
  • Delivered production-ready back-end services for core features, including payment distribution, raffle systems, and internal admin tools—all designed for horizontal scalability and high reliability from day one.
  • Achieved a successful beta release by rapidly building fully functional back-end components, enabling early user engagement.
  • Designed a clean and testable architecture, background job handling via Hangfire, and asynchronous processing for critical workflows.
  • Focused on performance and stability, ensuring all services met the uptime and latency expectations.
Technologies: C#, PostgreSQL, LINQ to DB, ASP.NET Core, Sentry, Hangfire, SQL, .NET, REST APIs, Microservices, APIs, ASP.NET, Windows, Git, REST, API Development, Back-end Development, RESTFul APIs, API Design, Back-end, Fintech, GitHub, JavaScript, Bug Fixes, C#.NET

Senior Software Engineer

2018 - 2020
Logican Solutions
  • Developed and maintained a CRM system for the company’s primary client, working on both the back-end services (SQL Server-based) and a WPF desktop application, enabling streamlined case and client management.
  • Served as the lead back-end developer for the Customer Portal, a web application that allowed end clients to interact with the business directly, improving customer satisfaction and reducing support overhead.
  • Delivered new business-critical features that enabled the client to expand operations, automate manual workflows, and serve more customers efficiently.
  • Led back-end development of a lawyer-facing portal for legal contract management, including data collection workflows and automated document generation using .NET Core and Vue.
  • Ensured robustness and maintainability through clean architecture, dependency injection, test automation, and message-based communication via RabbitMQ.
Technologies: C#, Entity Framework, SQL Server 2016, Windows Presentation Foundation (WPF), Telerik WPF, Vue, SQL, .NET, Azure, REST APIs, APIs, ASP.NET, Microsoft SQL Server, Windows, Git, Transact-SQL (T-SQL), Visual Studio, Windows Server, REST, API Development, Back-end Development, Database Design, RESTFul APIs, API Design, Back-end, Fintech, RabbitMQ, JavaScript, Azure Event Hubs, Azure PaaS, Bug Fixes, C#.NET

Senior Software Engineer and Unit Manager

2017 - 2018
EPAM Systems
  • Worked on a large-scale investment rebalancing platform for Barclays, one of the UK’s largest financial institutions.
  • Designed and delivered a modular task orchestration infrastructure capable of executing dynamic sequences of financial operations in parallel, enabling fast, scalable, and flexible fund processing.
  • Led a team of developers, overseeing task distribution, architecture decisions, and code quality, while coordinating closely with business analysts and QA.
  • Accelerated customer feedback cycles by rapidly delivering new features for early validation, allowing the client to experiment and adapt functionality to real business needs.
  • Built a fast, minimalistic WPF-based UI for internal users, combining clean UX design with strong performance and maintainability.
  • Contributed to both front-end and back-end development with a focus on testability, extensibility, and clean architecture.
Technologies: C#, Windows Presentation Foundation (WPF), Entity Framework, SQL Server 2016, NUnit, Moq, Team Management, Technical Requirements, SQL, .NET, APIs, Microsoft SQL Server, Windows, Git, Telerik WPF, Transact-SQL (T-SQL), Visual Studio, Back-end Development, Database Design, API Design, Back-end, GitHub, Technical Leadership, .NET Framework, Bug Fixes, C#.NET

Senior C# Developer

2016 - 2017
Sateva
  • Developed a desktop application from scratch for mining and engineering needs.
  • Supported and updated the back-end functionality of the app.
  • Wrote unit tests for most parts of the application using xUnit.
Technologies: C#, DevExpress, Windows Forms (WinForms), SQL Server 2016, NLog, xUnit, SQL, .NET, Microsoft SQL Server, Windows, Git, Telerik WPF, Transact-SQL (T-SQL), Visual Studio, API Development, Back-end Development, Database Design, GitHub, .NET Framework, Bug Fixes, C#.NET WinForms, C#.NET

Software Engineer

2015 - 2016
Top End Nurses
  • Created an excellent application for nursing home clinical compliance. It is a client-server application based on WCF framework as a service, MongoDB as a database, and WPF as the user interface.
  • Created unit, integration, and UI tests for the entire application.
  • Monitored and optimized the performance of the application.
Technologies: C#, MongoDB, NUnit, Windows Presentation Foundation (WPF), Windows Communication Foundation (WCF), MVVM Light Toolkit, Model View ViewModel (MVVM), .NET, Windows, Git, Visual Studio, API Development, Back-end Development, .NET Framework, Bug Fixes, C#.NET

Software Engineer

2015 - 2015
Rosneft
  • Developed an application that calculated the level of liquid in a sorbent during the absorption process.
  • Integrated the software into the Rosneft environment in fields.
  • Communicated with the customer directly to collect, analyze, and document requirements and specifications.
Technologies: C#, SQL Server 2014, Transact-SQL (T-SQL), NUnit, Windows Forms (WinForms), Windows Presentation Foundation (WPF), NLog, SQL, .NET, Microsoft SQL Server, Windows, Git, Visual Studio, Database Design, .NET Framework, Bug Fixes, C#.NET

Software Developer

2012 - 2015
Schlumberger
  • Developed several desktop applications for oil industry.
  • Prepared the product launch and commercialization.
  • Analyzed the requirements and specifications of the customer.
  • Managed the team of contractors and planned the scope of work for them.
  • Reviewed the code and tested the software based on industry standards.
Technologies: C#, Windows Forms (WinForms), Windows Presentation Foundation (WPF), DevExpress, R, Team Management, Requirements, Product Analytics, .NET, Windows, Visual Studio, .NET Framework, Bug Fixes, C#.NET WinForms, C#.NET

C# Developer

2010 - 2012
Data East
  • Developed the Forester–GIS toolkit to manage the forest resources of the UK.
  • Created modules that worked with a collection of statistical information and its editing.
  • Built tools to import old customer data to the new format for use in Forester application.
Technologies: C#, ArcGIS, Oracle, SQL, .NET, Windows, Visual Studio, Python, .NET Framework, Bug Fixes, C#.NET WinForms, C#.NET

Experience

Fashion Dress-up Game, SUITSME

https://suitsme.club/
I led back-end engineering for SUITSME, a mobile fashion game with up to 100,000 daily active users. I designed and delivered the back-end architecture from scratch, achieving 99.99% uptime and seamless scalability.

Self-care App, FABU

https://fabu.care/
I led back-end engineering for a self-care app for emotional support. I designed and delivered the back-end architecture from scratch, achieving 99.999% uptime, seamless scalability, and fast developer onboarding.

Tawasal

https://tawasal.ae
Tawasal is a secure multi-purpose messenger and super app that offers free calls, chats, video conferencing, and lifestyle services.

As a back-end developer, I created the raffle service and integrated it with other services and third-party APIs.

Education

2005 - 2011

Master's Degree in Computer Science

Novosibirsk State University - Novosibirsk, Russia

Skills

Libraries/APIs

Entity Framework, Windows Forms (WinForms), API Development, Moq, REST APIs, Vue, ArcGIS, Linq2SQL

Tools

JetBrains Rider, xUnit, Visual Studio, GitHub, C#.NET WinForms, Git, Sentry, Hangfire, Amazon Simple Queue Service (SQS), RabbitMQ, TeamCity

Languages

C#, C#.NET, Transact-SQL (T-SQL), SQL, R, Python, JavaScript

Frameworks

.NET Core, Entity Framework Core, ASP.NET Core, Windows Presentation Foundation (WPF), NUnit, MVVM Light Toolkit, .NET, ASP.NET

Paradigms

REST, Database Design, Microservices, Object-oriented Design (OOD), Microservices Architecture, Model View ViewModel (MVVM)

Platforms

Windows, Amazon Web Services (AWS), AWS Lambda, Telerik WPF, Azure, Windows Server, NLog, Oracle, Docker, Azure Event Hubs, Azure PaaS

Storage

PostgreSQL, SQL Server 2016, Microsoft SQL Server, MongoDB, SQL Server 2014, MySQL, Redis

Other

LINQ to DB, Back-end Development, RESTFul APIs, API Design, Back-end, .NET Framework, Bug Fixes, Computer Science, Team Management, APIs, Architecture, Cloud, WebSockets, Fintech, Technical Leadership, Technical Requirements, DevExpress, Windows Communication Foundation (WCF), Requirements, Product Analytics, C# Operators

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