Kiril Kamenev

I designed and implemented the core part of a platform for automating the configuration of communication networks. The intention was to build a replacement for an existing system that did not meet several non-functional requirements, including performance, scalability, and fault tolerance. The new system addressed existing issues by applying some architectural principles, such as message-driven communication, event sourcing, consistent hashing, scalable NoSQL data store, and non-blocking execution. Proper application of these techniques resulted in a reliable framework that was consistently used across all relevant microservices. One of the key challenges was to develop a mechanism to ensure exactly-once message processing semantics on top of the Kafka message bus.

In 2017, I started working on a project that eventually became the system that the Finnish Gymnastics Federation uses to host all of its competitions (over 200 per year, about 1000 to date).

The system includes features for athletes, event organizers, and the general public. I designed and implemented the system from the ground up using Spring Boot and Angular.

I also addressed all the issues related to running the service: deployment, upgrades, backups, occasional outsourcing of some work to freelancers, etc. The system provided many benefits for all user groups:

• Improved productivity for event organizers through rich and functional UI and a paperless real-time scoring system.
• Improved visibility and control for the Federation through reporting and centralized management.
• Better experience for the public through a responsive UI and real-time access to competition results as well as results archives.
• Easy integration for media (TV, online streaming) to embed scoring data in their content.
The system consistently gains high scores in surveys performed by the Federation.

In response to COVID-19 lockdowns, I developed a platform facilitating virtual competitions where participants' performances are recorded on their phones, uploaded to the server, and later automatically streamed to judges and the general public.

The system included a mobile app for recording the video and enforcing constraints (time window, number of attempts, etc.) and a management web application (React).

The integrated solution includes a video-on-demand service, streaming software (OBS), ticket sale system, and end user mobile app. Many parts of the system required real-time communication implemented with web sockets.

Over 100 competitions were hosted via the system during the lockdowns, which helped keep children active and motivated.

A secure platform that allows the integration between NFC payment ecosystem players: banks, credit card transaction processors, mobile device manufacturers, and telecom operators. The platform enables the provisioning of any payment app from any bank on any device without countless point-to-point integrations. The platform complied with the strictest security requirements of the banking industry.

This is an application enabling easy video content integration into Shopify stores. The application consisted of two parts: an administration UI for the merchant and the actual JavaScript application embedded into the store that adds required functionality.