James Seppi
Staff Software Engineer (Tech Lead) at Umbra
Austin, Texas, United States
Summary
🤩
Rockstar🎓
Top SchoolJames Seppi is a Staff Software Engineer and tech lead in Austin with 15 years building production-critical systems across geospatial, mapping, and satellite domains. He codes primarily in Python and TypeScript/JavaScript and currently architects the automated ground control and command systems for a Synthetic Aperture Radar satellite constellation. James has a strong track record at Mapbox and government agencies where he led low-downtime database migrations, high-throughput APIs serving billions of daily requests, and platform improvements that reduced cost and latency while preserving strict SLAs. He contributes to notable open-source projects like mapbox-gl-js and simple-statistics, spanning both front-end UX work and backend algorithmic additions. Comfortable operating in distributed teams, he blends hands-on engineering with mentoring, stakeholder engagement, and measurable operational improvements. His background in environmental and water resources engineering informs a pragmatic, data-driven approach to building resilient spatial systems.
15 years of coding experience
11 years of employment as a software developer
MS, Environmental and Water Resources Engineering, MS, Environmental and Water Resources Engineering at The University of Texas at AustinThe University of Maryland, College Park
Spanish, Chinese, English
Github Skills (23)
map-box10
javascript10
mapbox-gl10
mathematics10
css10
statistics10
typescript10
ui-design10
math10
doc10
uid10
front-end-development10
typescript-types10
html10
maps10
Programming languages (18)
Github contributions (5)
mapbox/mapbox-gl-js
May 2018 - Apr 2021
Interactive, thoroughly customizable maps in the browser, powered by vector tiles and WebGL
Role in this project:
Front-end Developer
Front-end DeveloperContributions:10 reviews, 10 commits, 18 PRs in 2 years 11 months
Contributions summary:James primarily worked on updating the page shell component, which likely provides the overall structure and styling for the web application. Their contributions included modifying JavaScript and CSS files related to the page shell, integrating new features, and improving the user interface. These changes suggest a focus on front-end development, with the aim of improving the application's appearance and user experience. Additionally, the user updated the mapbox-gl-geocoder plugin in multiple example files.
vector-tilestilesmonorepobrowsermapbox
simple-statistics/simple-statistics
Jan 2014 - Jul 2015
simple statistics for node & browser javascript
Role in this project:Back-end Developer
Back-end DeveloperContributions:6 commits, 1 PR, 1 issue in 1 year 6 months
Contributions summary:James primarily contributed to the implementation of new statistical functions within the `simple-statistics` library. They added features such as `harmonic_mean` and `root_mean_square`, and made updates to existing documentation and tests. Their work included modifying the core JavaScript files and adding corresponding tests to ensure the accuracy and functionality of the newly implemented statistical methods. Additionally, the user corrected a spelling mistake within the code.
regressionmathstatisticsbrowserjavascript
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