Hi

I'm Rafał. Welcome to my website.

I'm a software engineer from Poland, and this site is primarily for recruiters and engineers involved in the recruitment process.

I created this site in 2014 to make the recruitment process more efficient. At the time, many job offers I received were either not relevant to my experience or didn't align with my expectations. So, I always asked recruiters to visit for_recruiters page first, where I tried to address the most common questions typically asked in the first phase of interviews.

Over the years, the percentage of recruiters and engineers who visited my page before contacting me has grown from about 10% to 75%, so I believe it serves its purpose.

Skills Summary

This section should give a quick overview if I'm a good match for a potential role.

Years of experience

  • 18+ years as a software engineer
  • 9 years experience in managing teams and leading development process
  • 16+ years of Agile (Scrum, Kanban, mix, custom variations). Two training sessions led by Alistair Cockburn
  • 10+ years of remote work (USA, Ireland, Switzerland, Estonia)
  • 4+ years in start-ups
  • 2+ years ETL
  • 1.5 years in adapating AI models (prediction of energy consumption)
  • 5.5 years in e-payments
  • 4 years in various blockchain projects (almost 3 building DeFi)
  • 9+ years in iGaming
  • 1.5 years in building IoT
  • Linux (20+ years)
  • Experienced software architect with a strong foundation in cloud architecture patterns and system design best practices
  • Skilled in hands-on implementation of solutions, including designing and building ETL systems, and successfully leading the migration of monolithic applications to microservices for scalable, resilient infrastructures.

Programming languages

  • Elixir (6+ years)
  • Go (5+ years)
  • Python (6 months)
  • C#/ASP.NET (4 months)
  • Ruby (6 months)
  • Kotlin & Java (6 months)
  • JavaScript (10+ years)
  • PHP (when 5.6 was popular)

I held the following responsibilities as a lead:

  • Leading new feature development, maintenance, and operation activities
  • Managing the Engineering team consisting of engineers and quality assurance
  • Facilitating transparency and open communication
  • Optimizing operational efficiency by effectively managing resources
  • Developing and maintaining the team's culture
  • Facilitating design and architecture discussions and decision-making to ensure business requirements are translated into working software systems
  • Conducting 1:1s
  • Collaborating with product management to translate company strategy and goals to the execution level
  • Tracking project metrics to provide realistic updates
  • Working directly with clients and their technical teams

Certifications

  • Ignite Leadership Development Program (Human Synergistics)
  • Competency Based Interview Skills Workshop (Sapient)
  • ITIL V3 Foundations
  • Searching and Reporting with Splunk 5.0
  • I worked for two companies that were ISO 270001 certified

Databases

  • Postgres (7+ years)
  • MySQL (9+ years)
  • MongoDB (6+ months)
  • CouchDB (2 years)
  • Oracle (6 months
  • MS SQL (2 years)
  • Suppabase (6 months)
  • DynamoDB (3+ years)
  • ClickHouse (6 months)

Cloud

  • GCP (5+ years)
  • AWS (6+ years)
  • Heroku (2+ years)
  • Gigalixir (1 year)
  • I am able to optimize costs by migrating the infrastructure to more cost-effective cloud solutions.

Infrastructure setup / DevOps

  • Kubernetes (6+ years) and Openshift (2+ years)
  • Terraform (6+ months)
  • Ansible (1.5+ years)
  • Puppet & Vagrand (3+ years)
  • setting up CI/CD - gitlab, github, bitbucket (11+ years)
  • Docker (7+ years)
  • I am capable of setting up the infrastructure on my own.

Message queuing

  • RabbitMQ (4+ years)
  • GCP Pub/Sub (3+ years)

API

  • REST (10+ years)
  • GraphQL (6+ years)
  • gRPC (2+ years)
  • microservices (10+ years)

Caching

  • Redis (5+ years)
  • Memcached (8+ years)
  • Squid (3 years)
  • Varnish (3+ years)
  • ETS (6+ years)

Observability

  • Sentry (5+ years)
  • AppSignal (5+ years)
  • DataLog (6+ months)
  • Prometheus & Grafana (4+ years)
  • NewRelic (5+ years)
  • Splunk (3+ years)
  • Elasticsearch, Fluentd, Kibana (2+ years)

Some additional numbers

  • 300k of concurent players
  • $800 per second via payments API
  • 15k DB transactions / second
  • deploying to 500k MySQL DBs
  • 6 years of on-call
  • improved games integrations process (the technical part) from ~6 months to 0.5 - 2 days
  • most of the frontends I built backend for, were written in React, Vue, Phoenix LiveView and mobile Apps (Flutter, React Native, iOS, Android)

Awards

  • 1st Degree Award from the Rector of Wrocław University of Technology for Outstanding Achievements Among Students
  • EGR Operator Innovation Award 2013 - "Innovation in mobile and tablet" for Paddy Power team I led at the time