Paul Keen, Leadership Developer in Lviv, Lviv Oblast, Ukraine
Paul Keen

Leadership Developer in Lviv, Lviv Oblast, Ukraine

Member since June 3, 2019
Paul is a personal consultant with 15+ years of experience in full-stack software development. He architects solutions that are easy to support and scale, implementing best coding and management practices by continuous improvement of technical approaches. He focuses on test-driven development and is a Kanban practitioner.
Paul is now available for hire




Lviv, Lviv Oblast, Ukraine



Preferred Environment

MacOS, Kanban, CircleCI, Heroku, GitHub

The most amazing...

...experience was as a top 100 Ruby on Rails contributor where I helped numerous open-source projects like Ruby on Rails (Top100), Bundler, and more.


  • Co-founder

    2008 - PRESENT
    • Provided technical consultations to the clients, building a successful strategy, effectively structuring teams and processes.
    • Delivered scalable web and mobile applications using Ruby on Rails and modern JavaScript frameworks (Node.js, React, Vue.js, AngularJS).
    • Developed a framework for simple collaboration to reduce waste in product development. Clients distinguish communication approaches as a critical factor for mutually beneficial cooperation with us.
    • Designed code practices to help the team deliver a stable product. It improves team effectiveness and guarantees the quality and scalability of provided solutions.
    • Built strong partnership with clients like Moscow Institute of Physics and Technology (Top 3 University of Russian Federation), DefMethod, Knight Foundation, and others.
    Technologies: AngularJS, Node.js, Vue.js, React, Ruby on Rails (RoR)
  • React Native developer

    2019 - 2020
    Gilad Novik (via Toptal)
    • Upgraded old React Native application to use last React Native 0.61 and React Native Navigation from 1.x to 4.x.
    Technologies: Navigation, React Native
  • Senior Full-stack Engineer, Partner

    2014 - 2018
    Agent Inbox (via JetThoughts)
    • Contributed to the growth and recognition of Agent Inbox, the world's leading real estate messaging platform.
    • Designed technical architecture, mentored team, and resolved problems of product users.
    • Solved problems that restricted the team's ability to deliver the product reworked the previous solution simplifying the code base, optimized the development process using Lean principles.
    • Delivered the first MVP within two months which allowed founders to attract the investors and customers as well as increase the investments to scale the development.
    • Reduced risks of having new bugs implementing the development optimization: introduced code review, eliminated unnecessary routines and integrated automatized tests, which significantly reduced the cost of new developers onboarding process.
    • Scaled team to six developers in one year.
    • Implemented the high standards for code solutions got companies willing to acquire the product.
    Technologies: SAML, RETS, React, React Native, Ruby on Rails (RoR)
  • VP Engineering, R&D Director

    2014 - 2017
    Faria Education Group (via JetThoughts)
    • Managed full-cyсle of product development and design architecture improvements for Open Apply. The technology stack is based on Ruby on Rails and React.js.
    • Improved collaboration with related departments to organize effective product updates. Was responsible for growing R&D office in Ukraine.
    • Built long term refactoring strategy to simplify the code base, it increased team effectiveness by 20% in 3 months.
    • Removed high-performance computing operations for application and tests, which reduced running the whole test suite time from 1 hour to 15 min. As a result, the team was willing to add more checks to prevent regressions, and the cost of adding a new feature was decreased by $33,000 per month.
    • By integration, Lean principles and automatized tests prevented the accretion of new regression bugs. A list of known bugs was reduced from 500 to 10 within 3 months instead of growing each month, as it was before.
    • Helped the team to deliver a full redesign of the legacy functionality in 2 weeks instead of an estimated 3 months.
    • Integrated code and management practices to scale the team of developers from 5 to 20 in 6 months without any velocity decrease.
    Technologies: Amazon Web Services (AWS), AWS, PostgreSQL, React, Ruby on Rails (RoR)
  • Senior Full-stack Engineer

    2012 - 2014
    BigBinary (via JetThoughts)
    • developed code practices to have Ruby on Rails Testable Architecture.
    • Created processes to run a remote development team.
    Technologies: PostgreSQL, Ruby on Rails (RoR)


  • Agent Inbox (Development)

    Agent Inbox envisioned taking real estate communication to the next level. They hired us to build the right platform, deliver a market-ready solution, and help the team grow.

    - Set up a transparent process
    - ​Built R&D team: scaled from 1 developer to 10 developers
    - ​Got customer satisfaction and business recognition
    - Led strategy and directed scaling, architecture, engineering, supervised product and data, science teams
    - Responsible for developing technology platforms and mobile products using front-end frameworks including Ruby on Rails/React/React Native with REST APIs
    - Developed data pipelines for driving massive ETL architectures to support extraction, ingestion, formatting, and matching of data
    - Automated of CI/CD pipelines using the following technologies: Docker, Kubernetes, GitHub
    - Delivered production systems with real-time monitoring, alerting, and logging to reduce the needs of having operational staff
    - Provided direct support to founders for M&A discussions for product acquisitions

  • Open Apply (Development)

    As its client base grew, Faria Education Group (FEG) needed to ensure its OpenApply product could accommodate increasing demand. The problem? There were a lot (and we mean…a lot) of bugs within the code, and FEG didn't have any governing project management structure or unified documentation processes in place to address the growing issue.

    - ​Set up a transparent process
    - ​Applied practices to deliver changes with confidence
    - Built R&D team: scaled from 2 to 20 developers and QA
    - Increased sales and customer satisfaction
    - Enhanced code readability for better product performance. We drastically enhanced the product’s code readability to set the product up for current and future success. Our code quality rank on Code Climate was raised from level F to A. Plus, we significantly reduced bug risks by introducing code practices and efficient tests.
    - Improved rendering for faster performance. We reduced the average request processing time from 3 seconds to 0.2 seconds, and the average page rendering time dropped from 600 ms to 200 ms.

  • Knight Foundation (Development)

    Knight Foundation is a national foundation with strong local roots. They invest in journalism, in the arts, and in the success of cities where brothers John S. and James L. Knight once published newspapers.

    - ​Set up a transparent process
    - ​Applied practices to deliver changes with confidence
    - ​Production release decreased from 1 day to 0.5 hours

  • Mobile Coach (Development)

    Mobile Coach is a game-changing innovation for how enterprises influence employee engagement, learning, customer service, sales performance, and overall behavior change.

    - Set up a transparent process
    - Applied practices to deliver changes with confidence
    - Built R&D team: scaled from 2 to 10 developers
    - Increased sales and customer satisfaction

  • Campsyte (Development)

    Campsyte was created with a vision to build better cities. The cities have become less affordable and more fragmented, and Campsyte seeks to give people a sense of ownership and belonging, and together build happier cities.

    - ​Set up a transparent process
    - ​Delivered beta in short time after all
    - Helped to get paying users in just a few months


  • Languages

    JavaScript, Ruby, TypeScript, Bash, Haml, Sass, Crystal, SAML
  • Frameworks

    Ruby on Rails (RoR), Capybara, minitest, Factory Girl, Bootstrap 4,, AngularJS, React Native, Tailwind CSS
  • Libraries/APIs

    jQuery, Ruby ERB, React, Vue.js 2, Node.js, Vue.js
  • Tools

    RubyMine, Docker Compose, JavaScript Testing, CircleCI, GitHub, RSpec
  • Paradigms

    Test-driven Development (TDD), Continuous Integration (CI), Continuous Deployment, Kanban, Agile, Design Patterns, REST, Web Architecture, Web Application Architecture, UX Design
  • Platforms

    Docker, Heroku, MacOS, Linux, Director, Kubernetes, Amazon Web Services (AWS)
  • Storage

    PostgreSQL, MySQL, AWS S3
  • Other

    Leadership, Lean Development, Team Leadership, Remote Work, Remote Team Leadership, QA Automation, Technical Leadership, APIs, Customer Success, Account Management, Infrastructure, Executive Coaching, AWS, Navigation, Material Design, Scrum Master, RETS


  • Master's degree in Applied Mathematics
    2002 - 2007
    Donetsk National University - Ukraine


  • Functional Programming Principles In Scala
  • Computing For Data Analysis
  • Machine Learning

To view more profiles

Join Toptal
Share it with others