Sergii Vdovareize

Senior Frontend / Fullstack Engineer

Summary

I have over 15 years of experience as a software engineer with a strong focus on frontend and product-oriented development. My background spans multiple domains including EdTech, Healthcare, Video Advertising, Telecom, and Web Platforms.

I’ve worked in small cross-functional teams where versatility is critical, as well as in large-scale enterprise environments with clearly defined roles and delivery pipelines. This experience has given me a solid understanding of architecture decisions, performance optimization, CI/CD, automated testing strategies, accessibility standards, analytics, and product growth mechanics.

I focus on building scalable, measurable, and maintainable systems. I continuously look for ways to improve performance, increase test coverage, automate workflows, enhance UX, and strengthen engineering culture.

Experience

Lead Software Engineer — Clario

Aug 2024 – Present Lviv

Designing and scaling product-oriented applications with a focus on performance, analytics, UX optimization, and growth funnels.

Technologies: JavaScript, TypeScript, React, Next.js, Nest.js, Node.js, Playwright, Stripe
  • Building and optimizing sales funnels to increase conversion and customer lifetime value
  • Applying UX and behavioral design strategies to improve acquisition and retention
  • Setting up analytics and tracking systems for data-driven decision making
  • Designing automated visual regression testing workflows
  • Maintaining UI consistency and preventing production regressions

Senior Software Engineer — Beetroot

Mar 2020 – Jun 2024 Kharkiv / Lviv

Project: Inspera (Digital Assessment Platform)

A global assessment ecosystem used by educational institutions and professional organizations.

Technologies: JavaScript, TypeScript, React, Node.js, Java, Mocha, Sinon, Enzyme, Puppeteer, Percy, TeamCity, SonarCube
  • Led development of major frontend features and platform improvements
  • Led a frontend team of 5 engineers and reduced onboarding time
  • Increased automated test coverage by 300%
  • Integrated visual regression testing, reducing visual bugs 3x
  • Implemented SVG theme automation to improve accessibility
  • Contributed to achieving WCAG 2.1 AA compliance
  • Added integration tests validating API integrity
  • Contributed to video and audio proctoring systems
  • Improved secure browser functionality
  • Strengthened long-term client retention through consistent platform improvements

Senior Frontend Engineer — Team International

Sep 2018 – Feb 2020 Kharkiv

Client: Telenor Denmark

Large telecom provider with 1.4M+ customers.

Technologies: JavaScript, React, Node.js, REST, Tealium, Adobe Analytics, TeamCity
  • Participated in full redesign of the main customer portal
  • Improved engagement and conversion metrics
  • Implemented and maintained Tealium Tag Management
  • Integrated Adobe Analytics tracking (marketing effectiveness +30%)
  • Built client-side reporting tools
  • Supported sales campaigns (+10% sales during campaign periods)
  • Conducted internal training sessions

Full Stack Software Engineer — Verizon Media (Oath / AOL)

Apr 2016 – Jul 2018 Dublin

Project: One by AOL (Programmatic Video Platform)

Technologies: JavaScript, Java, Node.js, MongoDB, Jasmine, Nightwatch, Jenkins, S3, Datadog
  • Developed high-performance HTML5 video player
  • Increased ad revenue through new provider integrations
  • Designed and maintained Player Version Manager (95% auto-update success rate)
  • Reduced production issues 10x via automated version control
  • Improved unit, UI, and mobile test coverage by 50%
  • Enhanced CI/CD processes
  • Refactored player into modular micro-components

Full Stack Software Engineer — Sigma Software Group

Dec 2014 – Apr 2016 Kharkiv

Project: Vidible (Video Advertising Platform)

Technologies: JavaScript, Java, Ruby, Gradle, MongoDB, Jenkins, RSpec, JUnit
  • Extended and supported backend services
  • Enhanced video player functionality
  • Developed ad platform UI features
  • Introduced new video ad providers
  • Implemented player version switcher
  • Automated deployment flow (50% faster releases)

Software Engineer — Samsung Ukraine R&D Center

May 2013 – Dec 2014 Kharkiv
Technologies: Tizen OS, Tizen API, JavaScript, jQuery, Java, Android, Jenkins
  • Developed Tizen web-based reference applications
  • Built smart watch applications
  • Implemented smartphone–wearable interaction protocols
  • Worked on framework-level solutions for web apps
  • Optimized performance, memory usage, and battery consumption
  • Improved UI/UX for mobile and wearable environments

Backend / Frontend Developer — Software Expert

Apr 2008 – May 2013 Kharkiv
Technologies: PHP5, CodeIgniter, Symfony, JavaScript, MySQL, Selenium, WebOS, Blackberry
  • Implemented backend functionality for multiple web projects
  • Designed database architecture
  • Built reusable UI widgets (calendar, price calculator, rental forms)
  • Integrated OAuth, Google APIs, IMAP
  • Developed mobile applications (WebOS, Blackberry)
  • Implemented Selenium-based UI testing
  • Improved UX across multiple products