As a senior developer with most experience in Back-End I was mainly responsible for API integrations with 3rd party external services. Capability of fast integration with other companies allowed client to be recognized and establish new business relationships. I was also responsible for creating new features and maintaining existing ones. I was working with a team of 3 developers with different level of seniority from junior to tech lead. I was responsible for code reviews and aiding other developers in their work. I was working with technologies and gems like Rails 5.2, 6.0, grape, swagger, sidekiq, postgres, minitest and RSpec, VUE.js, stimulus and others.