Sean Colsen
Software Engineer at Mathesar Foundation
Boston, Massachusetts, United States
Summary
🤩
Rockstar🎓
Top SchoolSean Colsen is a seasoned full-stack software engineer with nine years of experience, currently contributing to Mathesar, an open-source spreadsheet-database hybrid used to view and edit Postgres data. He leans front-end with a passion for TypeScript while also bringing strong back-end and security expertise—having hardened input validation and XSS defenses in CiviCRM and fixed multiple upstream vulnerabilities. Sean has led UX design and architectural discussions in distributed teams, migrated legacy front ends to modern stacks like Nuxt/TypeScript, and built data-focused B2B SaaS features and large-scale web scrapers. Practical and detail-oriented, he pairs UI polish (focus/blur handling, alignment fixes) with security-first thinking, making interactive features both usable and safe. Based in Boston, he combines open-source contributions with freelance and nonprofit experience, including migrating a decade of documentation and building custom publishing tooling.
9 years of coding experience
15 years of employment as a software developer
Bachelor's degree Electrical Engineering, Bachelor's degree Electrical Engineering at Northeastern University
Github Skills (16)
typescript10
php10
typescripts10
svelte10
frontend10
front-end-development10
input-validation10
web-frontend10
xss10
typescript-types10
ui-components10
security10
smarty9
mysql7
apidoc7
Programming languages (16)
Github contributions (5)
mathesar-foundation/mathesar
Aug 2021 - Jan 2023
An intuitive spreadsheet-like interface that lets users of all technical skill levels view, edit, query, and collaborate on Postgres data directly—100% open source and self hosted, with native Postgres access control.
Role in this project:
Full-stack Developer
Full-stack DeveloperContributions:1 release, 750 reviews, 1177 commits in 1 year 5 months
Contributions summary:Sean contributed to the front-end UI components of the Mathesar spreadsheet-like interface, focusing on adding a new "Record Selector" for linking related records and updating existing UI elements within the application. These changes involved refactoring to align with the new features added. Additionally, the user implemented improvements to existing components, specifically text inputs, including handling focus and blur events and fixing alignment.
pythondjangouser-experienceweb-applicationintuitive
civicrm/civicrm-core
Feb 2017 - Apr 2018
CiviCRM (Core Application and Framework)
Role in this project:Back-end Developer & Security Engineer
Back-end Developer & Security EngineerContributions:58 commits, 21 PRs, 77 comments in 1 year 2 months
Contributions summary:Sean primarily focused on improving the security of the CiviCRM core application by introducing and implementing input validation techniques. They added an 'Alphanumeric' rule type for validating GET parameters, hardening inputs for "mode" parameters, and improved output escaping to prevent XSS vulnerabilities. Additionally, the user added HTML purification to status messages and implemented context validation. These changes indicate a strong focus on security best practices.
backbonejscivicrm
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