Karl Kallavus

I am a frontend developer and team leader with a strong technical background in building complex web applications. I am passionate about creating usable, performant, and maintainable solutions. With extensive experience in mentoring team members, I excel in fostering collaboration, driving project success, and leveraging my deep development expertise to guide strategic planning and problem-solving.

karl.kallavus@gmail.comhttps://github.com/karl-kallavus

Open Source Projects

Moon Design System - moon.io

Product design system that helps maintain and optimize design and development resources.

  • ex "Top 1 Trending" Design System in Figma Community.
  • > 35000 downloads.
  • > 30 contributors.

Technical Skills

Favorites:

TypescriptReactnext.jstailwindpnpm

Frontend:

ES2015/16/17HTMLCSSnpmyarnwebpack

Backend:

nodeGraphQLApollorelayelixirpython

Others:

gitcircleciDockerchangeset

Experience

  • Project Lead, Yolo Group, Tallinn, Estonia, Sep 2024 - Present

    • Successfully launched casino brands: bombaycasino.com and live.io
    • Led a high-performing development team: managed a team of 8 developers
    • Technology Stack: Utilized LiveView and Elixir

  • Frontend Team Lead, Yolo Group, Tallinn, Estonia, Jan 2021 — Sep 2024

    • Created Moon Design System from the scratch.
    • Managed and grew a frontend development team from 0 to 7 developers.
    • Integrated design system in ~12 different projects (e.g sportsbet.io, bitcasino.io, slots.io, hub88.io and many more)
    • Fostered a design system culture within the company.
    • Tracked customer satisfaction and other SLI metrics.

  • Fullstack Developer, Yolo Group, Tallinn, Estonia, Nov 2017 — Jan 2021

    • Developed sportsbet.io.
    • Using GraphQL impelemented almost all core product features.
    • Fixed site-speed issues, reduced global load times down from 18 seconds to just six for slow 3G connections.
    • Created design system from the scratch.

  • Frontend Developer, Genestack, Cambridge, UK / Saint-Petersburg, Russia, Mar 2016 — Nov 2017

    • Successfully introduced react/redux into major applications.
    • Responsible for frontend application architecture, development and UI implementation.

  • Fullstack Developer, Masshtab Research Institute , Saint-Petersburg, Russia, Nov 2014 — Mar 2016

    • JavaScript & Python development for both customer projects and internal products.
    • As the sole developer designed, built and managed the full application (nodejs backend, angular.js frontend)

  • Backend Developer, RAMAX International JSC, Saint-Petersburg, Russia, May 2014 — Nov 2014

    • Developed applications using Python and Oracle for database design.
    • Maintained and improved existing applications.

Talks

Nov 2019, TallinnJS, Estonia

Design Systems: Are they worth it?

There has been a lot of noise around Design Systems, some love them, some are skeptical. Based on my experience with our own Design System I'll separate the reality from hype. After this session, you’ll be able to make a decision about whether to invest your technology into a Design System armed with an understanding of the risks and benefits.

Articles

2018

The Need For Speed: Measuring web performance

Education

2007—2014, Master & Bachelor's degree with honors.

Saint-Petersburg Electrotechnical University "LETI", Russia.

Information Systems and Technologies.