Rafał Sebestjański
Highcharts Team Lead & Project Manager at Black Label
Krakow, Lesser Poland Voivodeship
Summary
🤩
RockstarRafał Sebestjański is a Highcharts-focused front-end engineer and team leader with nine years of experience building and supporting data-visualization solutions at Black Label. He blends hands-on JavaScript/TypeScript development—contributing bug fixes and annotation improvements to the widely used Highcharts library—with project management, client-facing implementations, and people leadership. A former support lead, he emphasizes building self-managing teams through coaching, clear processes, and close customer collaboration. His background as a long-time math tutor informs his knack for explaining complex concepts and tailoring solutions to different users. Outside work he brings the same methodical, ingredient-driven approach to the office pizza oven as he does to chart precision and performance.
9 years of coding experience
Polish, English
Stackoverflow
2,126reputation
52kreached
102answers
3questions
highcharts
top-1%
Github Skills (12)
debug10
javascript10
highcharts10
html9
css9
debugging9
shiny6
jquery6
r6
angular-highcharts6
angular6
charts6
Programming languages (5)
Github contributions (5)
highcharts/highcharts
Nov 2018 - Jan 2023
Highcharts JS, the JavaScript charting framework
Role in this project:
Front-end Developer
Front-end DeveloperContributions:530 reviews, 369 commits, 92 PRs in 4 years 2 months
Contributions summary:Rafał primarily contributed to the Highcharts library by fixing bugs and improving existing functionality related to annotations. Their work focused on ensuring the correct positioning and visibility of annotations, especially concerning features like series comparison, the use of multiple axes, and the integration with stock tools. They also addressed issues related to drag and drop behavior and overall performance, improving the user experience across different chart types.
chartshighchartschartchartingjavascript
blacklabel/highcharts-fundamentals
Apr 2022 - Jul 2024
02. Highcharts Fundamentals
Contributions:2 reviews, 5 PRs, 16 pushes in 2 years 3 months
highchartsfundamentalsdata-visualizationvisualization
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