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Hi! I'm Karol, I'm a Ruby on Rails expert and distributed systems architect, currently working as CTO at BookingSync.

Thanks to over 10 years of experience, working on difficult challenges and being committed to learning new things every day and reading all books I can find on the relevant topics, I had a chance to solve a variety of problems. Here are some notable initiatives I've had a chance to lead:

  • Grow engineering team from 5 to over 20 team members with scarce finances
  • Manage ecosystem of 27 distributed applications (and several Ember applications)
  • 350x improvement in data synchronization speed between services by replacing HTTP API-based data synchronization between services with Kafka-based Change Data Capture using a custom framework decreasing the average latency of data synchronization between services from over 30 minutes to sub-5 seconds (over 350x improvement), at the same using less than 30% resources (CPU, memory) on the consumers side compared to the previous architecture
  • Introduce event-based architecture and communication between services via RabbitMQ using a custom framework
  • Build PCI DSS compliant platform for credit data processing and maintain compliance through multiple years
  • Migrate from legacy Hephy Workflow PaaS and self-hosted Kubernetes to a modern infra built on top of AWS EKS, Helm, ArgoCD, Jenkins
  • Migrate 5 self-managed PostgreSQL clusters to AWS RDS service using AWS DMS
  • Migrate 3 self-managed Redis cluster to AWS ElasiCache
  • Decrease AWS infrastructure cost by approximately 35% through different initiatives (including the migrations mentioned above)
  • Introduce SPACE Framework as a developer productivity framework

My CTO archetype is an architect - while I've been de-facto VP of Engineering focusing on people management, I'm at my best when I design systems and keep my hands at least a little dirty, even if it's just a prototype or a proof of concept.

I strongly believe in always giving back. That's why I've been involed in many open source projects and have been sharing knowledge on multiple occasions (including writing a book and releasing it for free and writing articles on other blogs.).

If you need a consulting in any areas of my expertise, feel free to use the form below and send me a message.

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