Senior C# .NET Software Engineer at Growe
Budapest, Hungary
Serhii Yakhin
Council Member
Serhii Yakhin is a Senior .NET Software Engineer and Tech Lead with 10+ years of experience specializing in backend development, distributed systems, and cloud-native architecture. Based in Budapest, Hungary, he designs high-throughput microservices, leads platform modernization initiatives, and builds scalable systems using .NET, Kafka, and AWS, creating end-to-end observability solutions with real-time dashboards for performance monitoring and incident response. His focus is on creating clean, well-structured, and purpose-fit solutions that ensure stability, performance, and effortless scalability.
At Growe (November 2024 - Present), a leading advisory and services group in iGaming and Entertainment, Serhii serves as Tech Lead for a team that grew from 4 to 7 engineers, managing approximately 20 microservices across Integration and Engagement cells. The Integration Cell handles high-volume data processing from third-party partners including Facebook, Google, and Voluum, while the Engagement Cell powers user-facing systems including messaging, segmentation, and referral programs.
He architected the Segment Service using CQRS, Clean Architecture, and Kafka with Protobuf, achieving ~2,200 requests per second ingress with 10k batch loads and ~41,000 events per second Kafka produce throughput. He orchestrated the platform's largest data migration, successfully moving 50 million users from a legacy system in 36 hours while ensuring data integrity and service continuity. He also architected and implemented the Referral Service with REST, CQRS, Clean Architecture, full OpenAPI coverage, and a design supporting secure concurrent payment processing for eligible invitees.
He led migration of all team services to .NET 9 and piloted .NET 10/gRPC adoption, reducing technical debt and unlocking significant performance and tooling improvements. He implemented end-to-end telemetry using OpenTelemetry from scratch, creating dedicated Grafana dashboards per service and cross-team universal Kafka and .NET Application dashboards. He added custom metrics for segmentation throughput and SLOs, integrated alerting with PagerDuty and Slack, and materially reduced Mean Time to Resolution while improving signal-to-noise ratio in logs. He designed team-wide templated CI/CD pipelines with environment filtering, conditional tests, and auto-tagging, centralized NuGet package management for API clients and contracts, and automated bulk GitLab operations to accelerate configuration changes.
At EPAM Systems (December 2023 - October 2024), working on Mercedes-Benz connected vehicle platform for Daimler, he was a core engineer on an event-driven microservices solution for managing vehicle digital lifecycles. He independently developed standalone CLI applications within the Development Tools domain for API testing, Azure IoT Hub and Device Provisioning Service interactions, Azure Active Directory user management, and system diagnostics, streamlining developer workflows across teams. He was a primary contributor to core services including SoftwareService for Over-the-Air update lifecycle management, DeviceService as the digital twin for vehicles, and OrganizationService for authorization and RBAC. He contributed significantly to Fleet Delivery feature enabling simultaneous software deployment to tens of thousands of vehicles, implemented scalability improvements enabling tenfold increase in device capacity, and took ownership of resolving systemic support cases with architectural improvements reducing critical incidents by approximately 90%. During his tenure, he was instrumental in scaling the platform from 6 to 14 microservices.
At Growe (November 2024 - Present), a leading advisory and services group in iGaming and Entertainment, Serhii serves as Tech Lead for a team that grew from 4 to 7 engineers, managing approximately 20 microservices across Integration and Engagement cells. The Integration Cell handles high-volume data processing from third-party partners including Facebook, Google, and Voluum, while the Engagement Cell powers user-facing systems including messaging, segmentation, and referral programs.
He architected the Segment Service using CQRS, Clean Architecture, and Kafka with Protobuf, achieving ~2,200 requests per second ingress with 10k batch loads and ~41,000 events per second Kafka produce throughput. He orchestrated the platform's largest data migration, successfully moving 50 million users from a legacy system in 36 hours while ensuring data integrity and service continuity. He also architected and implemented the Referral Service with REST, CQRS, Clean Architecture, full OpenAPI coverage, and a design supporting secure concurrent payment processing for eligible invitees.
He led migration of all team services to .NET 9 and piloted .NET 10/gRPC adoption, reducing technical debt and unlocking significant performance and tooling improvements. He implemented end-to-end telemetry using OpenTelemetry from scratch, creating dedicated Grafana dashboards per service and cross-team universal Kafka and .NET Application dashboards. He added custom metrics for segmentation throughput and SLOs, integrated alerting with PagerDuty and Slack, and materially reduced Mean Time to Resolution while improving signal-to-noise ratio in logs. He designed team-wide templated CI/CD pipelines with environment filtering, conditional tests, and auto-tagging, centralized NuGet package management for API clients and contracts, and automated bulk GitLab operations to accelerate configuration changes.
At EPAM Systems (December 2023 - October 2024), working on Mercedes-Benz connected vehicle platform for Daimler, he was a core engineer on an event-driven microservices solution for managing vehicle digital lifecycles. He independently developed standalone CLI applications within the Development Tools domain for API testing, Azure IoT Hub and Device Provisioning Service interactions, Azure Active Directory user management, and system diagnostics, streamlining developer workflows across teams. He was a primary contributor to core services including SoftwareService for Over-the-Air update lifecycle management, DeviceService as the digital twin for vehicles, and OrganizationService for authorization and RBAC. He contributed significantly to Fleet Delivery feature enabling simultaneous software deployment to tens of thousands of vehicles, implemented scalability improvements enabling tenfold increase in device capacity, and took ownership of resolving systemic support cases with architectural improvements reducing critical incidents by approximately 90%. During his tenure, he was instrumental in scaling the platform from 6 to 14 microservices.
At CEX.IO (October 2019 - December 2023), a centralized cryptocurrency exchange, Serhii served as a core engineer in a small 4-person team responsible for the entire exchange transaction flow supporting over 27 blockchain networks. He spearheaded integration of 10 major blockchain networks including EVM and non-EVM chains like LUNA, NEAR, and FIO, along with dozens of associated tokens, directly enabling new revenue streams worth hundreds of thousands of USD. He architected complete integration flows encompassing SDK development for key creation, address generation, transaction signing, and hashing; high-throughput blockchain parsers handling smart contracts and multiple token types; internal Web APIs and RabbitMQ event-driven communication; and complex resilience logic for network finality and chain rollbacks. He developed a reusable framework for EVM-based chains accelerating new network integrations by approximately 30%.
Beyond his engineering work, Serhii is an active community contributor and speaker. During his time at EPAM Systems, he was a member and speaker for the internal .NET Kyiv Community, presenting on topics including .NET 9 Updates, .NET Aspire, new C# features, and .NET performance optimization. He holds a Master's Degree in Software Engineering from the National Technical University of Ukraine "Kyiv Polytechnic Institute" and co-authored a peer-reviewed publication on macroeconomic modeling. He conducted over 15 interviews at Growe resulting in 2 successful hires followed by ongoing mentorship, and consistently introduces incremental refactor patterns to pay down technical debt without blocking feature delivery. As a strong team player, he values open communication, knowledge sharing, and collaboration, believing that great teams, not just great code, are what make great products possible.
Beyond his engineering work, Serhii is an active community contributor and speaker. During his time at EPAM Systems, he was a member and speaker for the internal .NET Kyiv Community, presenting on topics including .NET 9 Updates, .NET Aspire, new C# features, and .NET performance optimization. He holds a Master's Degree in Software Engineering from the National Technical University of Ukraine "Kyiv Polytechnic Institute" and co-authored a peer-reviewed publication on macroeconomic modeling. He conducted over 15 interviews at Growe resulting in 2 successful hires followed by ongoing mentorship, and consistently introduces incremental refactor patterns to pay down technical debt without blocking feature delivery. As a strong team player, he values open communication, knowledge sharing, and collaboration, believing that great teams, not just great code, are what make great products possible.