Kelvin Abrokwa-johnson
Software Engineer at Jane Street
San Francisco, California, United States
Summary
🤩
Rockstar🎓
Top SchoolKelvin Abrokwa-Johnson is a software engineer in San Francisco with 11 years of experience building front-end and embedded systems across startups and top-tier firms like Jane Street and Square. He blends low-level embedded work—shipping hardware payment systems and mesh Wi‑Fi services—with polished JavaScript front-end contributions to widely used open-source mapping projects such as Mapbox GL and mapbox-gl-draw. His open-source commits address tricky UI/interaction and rendering problems (text shaping, fill patterns, and interactive geometry editing), reflecting a strong eye for correctness and user-facing detail. Comfortable across the stack, he pairs an Applied Computational Mathematics background with practical systems and data-pipeline experience from Google and Mapbox. Colleagues describe him as relaxed but effective—someone who quietly tackles subtle bugs that improve real-world reliability and developer experience.
11 years of coding experience
4 years of employment as a software developer
International Baccalaureate Diploma, International Baccalaureate Diploma at Stonewall Jackson High SchoolBachelor’s Degree, Applied Computational Mathematics, Bachelor’s Degree, Applied Computational Mathematics at William & Mary
English, French, Arabic, twi, ga
Github Skills (17)
webgl10
javascript10
mapbox-gl-js10
testing10
ui-design10
geojson10
uid10
front-end-development10
text-rendering10
maps10
user-interface9
event-handling9
interface-design9
typescript9
typescript-types9
Programming languages (7)
Github contributions (5)
mapbox/mapbox-gl-draw
Jul 2015 - Feb 2016
Draw tools for mapbox-gl-js
Role in this project:
Front-end Developer
Front-end DeveloperContributions:316 commits, 72 PRs, 332 pushes in 7 months
Contributions summary:Kelvin primarily focused on implementing the ability to draw and edit geometries within the `mapbox-gl-draw` repository. They added event listeners for drawing interactions, including click, mousemove, and mouseup events. The user's work included integrating draw tools (marker, line, polygon, and square) and implementing features like vertex manipulation, indicating a focus on UI and interaction design for the drawing functionalities.
mapboxdrawmapbox-gljavascriptmapbox-gl-js
mapbox/mapbox-gl-js
Jul 2015 - Jan 2016
Interactive, thoroughly customizable maps in the browser, powered by vector tiles and WebGL
Role in this project:Front-end Developer
Front-end DeveloperContributions:11 commits, 12 PRs, 47 pushes in 5 months
Contributions summary:Kelvin primarily contributed to the JavaScript code base of the `mapbox-gl-js` repository. They focused on features related to text rendering, specifically addressing line wrapping and text offset bugs within the symbol shaping functionality. Additionally, the user made contributions related to fill pattern rendering, ensuring seamless transitions and correct alignment across tile boundaries. Finally, the user updated test suites to match changes made.
vector-tilestilesmonorepobrowsermapbox
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