Fiachra Mcdermott
Senior Software Engineer at Mercury
San Francisco, California, United States
Summary
👤
Senior🎓
Top SchoolFiachra Mcdermott is a Senior Software Engineer based in San Francisco with 11 years of professional experience and seven years focused on backend engineering for eCommerce. He specializes in payments, checkout, and cart systems, having owned critical checkout APIs at Square and built end-to-end backend infrastructure as a founding engineer at a YC-backed startup. Comfortable across PHP/Laravel and Node.js, he deploys production systems on Kubernetes and AWS and emphasizes observability, scalability, and strict typing. An active open-source contributor, he has improved well-known static analysis tools like Psalm and Larastan—work that underscores his interest in static analysis and code quality. He mentors engineers, has led teams of seven-plus on year-long projects, and brings a pragmatic product-minded approach to platform problems. Colleagues value his mix of deep eCommerce domain expertise and a habit of improving tooling to reduce class-of-bug issues before they reach production.
11 years of coding experience
9 years of employment as a software developer
Bachelor of Science (B.S.) Information Technology (Design and Development Option), Bachelor of Science (B.S.) Information Technology (Design and Development Option) at Penn State UniversityLa Salle College High School
Github Skills (22)
application-framework10
type-inference10
static-analysis10
eloquent10
laravel-mix10
app-framework10
laravel10
sa10
php10
code-analysis10
exception-handling10
web-framework10
phpstan10
ps10
security9
Programming languages (14)
Github contributions (5)
larastan/larastan
Nov 2018 - Feb 2020
⚗️ Adds code analysis to Laravel improving developer productivity and code quality.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:7 commits, 16 PRs, 86 comments in 1 year 3 months
Contributions summary:Fiachra contributed to the larastan project by addressing bug fixes, implementing new features, and refactoring existing code. Their work focused on improving code analysis capabilities for Laravel, as evidenced by changes to return types, generic resources, and eloquent builder extensions. They also fixed issues related to dynamic wheres and transformed ide-helper relationship docblocks. These modifications enhance the project's ability to provide precise static analysis.
productivityphpdeveloper-productivityphpstancode-quality
vimeo/psalm
Apr 2020 - Oct 2020
A PHP static analysis tool for finding errors and security vulnerabilities in PHP applications
Role in this project:Back-end Developer
Back-end DeveloperContributions:12 commits, 23 PRs, 106 comments in 5 months
Contributions summary:Fiachra's contributions primarily focused on enhancing the functionality and maintainability of the PHP static analysis tool, Psalm. They addressed bug fixes related to type resolution and mixin parameters, improved code quality by marking strings as lowercase, and added features like memory limit specifications and universal object crates. Furthermore, the user contributed by providing documentation for the plugin hooks.
security-analysisfindingphptaint-analysisphp-applications
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