Working on a number of things Infrastructure related: tools, cost and latency optimization, stability and reliability, rate limiting, ArgoCD and services deployment in general, configuration management, helping product teams to improve their services.

Volunteering and contributing to the open-source ArgoCD system. Doing optimizations, bug fixes, issues triage and some community work. Check out contributions for my GitHub user names andrii-korotkov-verkada and andrii-korotkov.

Worked on the following:

* Supported Thrift (RPC framework) development. Developed a critical structured annotations feature from scratch achieving stronger type safety guarantees for an important customer. Migrated Thrift Hack object construction to safer and more convenient APIs by codemods. Marked a big part of Thrift Hack functions with capabilities achieving more automated safety guarantees. Languages: Hack/PHP, Yacc (a bit), C++ (a bit). 3 years.

* Services CPU Efficiency: Worked with a team on automation to capture functions CPU cost increase before and after releases saving up to $100sM per year in fixed regressions. Found and implemented optimizations in the existing codebase achieving 2%+ global web tier CPU wins. Worked with partner teams to manage their CPU usage long-term. Led a team during a transition from mainly optimizations made by the team to a more scalable approach with developer teams sharing more responsibility for their efficiency. Languages: Hack/PHP, Python. 3 years.

* Ranking and recommendations distributed system. Wrote and maintained backed services, trained ML models, did feature engineering. Wrote Hive jobs to process large volumes of data. Languages: Hack/PHP, C++, SQL-like. 2.5 years.

* Mentoring: Helped a junior engineer with a career for several years and had two interns.

Worked on testing system for MySQL. System tested replication, upgrade in process of replication and correctness of query results.

Working with distributed systems, optimizing services performance, developing services, writing tests.